NATIONAL FIREARMS MUSEUM -- Formerly the museum of the National Rifle Association, the National Firearms Museum in 1985 achieved independent (and tax-exempt) status as the first step in a campaign to become "nothing less than the leading firearms museum in America," as a curator put it.

The second step will be a fundraising campaign; meanwhile, about 800 of the museum's collection of more than 2,000 technologically and historically significant small arms are jam-packed into dusty display cases with a minimum of explanatory material. But anyone who finds firearms interesting will find this collection fascinating. Among the display pieces are President Reagan's muzzle-loader and late mystery writer Erle Stanley ("Perry Mason") Gardner's fancy six-shooter. At 1600 Rhode Island Ave. NW. Open 10 to 4 daily; free. 828-6194. WASHINGTON NAVY YARD -- From 1799 to 1961 it was mainly the U.S. Naval Gun Factory, and many of the weapons forged in the vast workshops still are at sea, ready to defend the fleet or, as in our confrontation with Qaddafi, to once again impose the will of the United States upon the shores of Tripoli.

Within this great walled compound along the Anacostia -- now an administrative and ceremonial center -- there is a sense of a simpler and more orderly day, and a walking tour is time well spent. A self-guiding map is usually available at the guard gate or at the Navy and Marine museums. It's a shame the Navy hasn't seen fit to open at least one or two of the shops so visitors could see the stupendous size and precision of the machines in what once was one of the principal arsenals of democracy.

At Ninth and M streets SE. Open to the public but, because this is an active military installation, the gate guards may require identification. Within the Navy Yard are: U.S. NAVY MEMORIAL MUSEUM -- Admiral Arleigh ("31 Knot") Burke established this museum in 1961, and the institution has always had a somewhat idiosyncratic air about it that regular visitors cherish. A major repair and refit, completed in 1985, brightened things up considerably but left most of the charms of "the Navy's attic" intact.

There are anti-aircraft guns the kids can elevate and train, periscopes through which you can draw a bead on the USS Barry (below) and on pleasure boats plying the Anacostia, trophies from great expeditions and foreign military adventures, wonderful ship models and a world of other neat stuff.

There are also oddities whose presence can be explained only by the fact that the donors were senior brass hats or their ladies, such as former Navy Secretary John Warner's pothole rock from Australia, which bears a striking resemblance to those to be found by the score along the Potomac Palisades.

Outside are newly remounted ranks of weapons ranging from antique expeditionary fieldpieces to an incredibly large 16-inch battleship gun and latter-day rockets. The museum is gradually shifting its emphasis to World War II. A Corsair fighter plane recently was hung from the rafters, along with a Japanese suicide glide bomb; other major WWII pieces will be added as time and Gramm-Rudman-Hollings permit.

Open 10 to 5 weekends and holidays, 9 to 5 weekdays; free. 433-2651. SUBMARINE MUSEUM -- Part of the old building that once housed the David Taylor Model Basin, closed since the new one was built in suburban Maryland, has been reopened to show off the Navy's submarine collection.

The initial display pieces include three WWII Axis two-man ("two-sucker") submarines. The German Seehund carried two torpedos; the Japanese Kaiten suicide boat was a torpedo; the Italian submersible was MILITARY MUSEUMS

MILITARY MUSEUMS abound in and around Washington. The armed services have their headquarters here, as do a number of patriotic societies. British forces focused on our capital during the War of 1812, and the Civil War saw some of the most dreadful battles the world has ever known rage along the corridor between Gettysburg and Petersburg.

The major battlefields have been preserved, and besides the extensive exhibits in their visitor centers, there are museums to be found in many of the towns and cities around -- or through -- which the armies surged. Beyond these are the major military museums maintained by the several services. Altogether, they make the Washington region a rich one for the militaria-minded. WASHINGTON ANDERSON HOUSE -- The headquarters and museum of the Society of the Cincinnati occupy one of Washington's great private houses, a turn-of-the-century dwelling built for U.S diplomat Larz Anderson in the last days before the institution of the income tax. The house and the European and Oriental antiques collected by Anderson make a sumptuous setting for the displays of the collections of the Cincinnati, founded in 1783 by officers who served in the Revolutionary War. Their descendants have not neglected the memory of the Continental Army, its commander, and most particularly its French allies, all memorialized by portraits, weapons and artifacts.

At 2118 Massachusetts Ave. NW. Open 1 to 4 Tuesday through Saturday; free. 785-0540. ARMED FORCES MEDICAL MUSEUM -- They used to call it the Army Medical Museum, and it used to be near the Mall; it was the most horribly fascinating place in town. The name and location have changed, but the Stone Baby and the Petrified Man and Dan Sickles' Leg and the specimen jars of mutilated or diseased organs and whatever all are still there, and the policy of free and full public admission still is in force.

The museum holds the collection of the Armed Forces Institute of Pathology, dating back to the Civil War (which might have been shorter if that cannonball had carried away General Sickles' head instead of his leg; at least it would have seemed shorter). Study of these samples of the horrors of war and disease has vastly improved medical knowledge and techniques, and the folks who run the place are mighty proud of it.

At the time of the Civil War even a relatively minor wound amounted almost to a death sentence, and the more "medical" attention a man received from the unwashed shamans of the day, the more likely he was to suffer fatal infection. These days an American battle casualty who doesn't die immediately will very probably live to see his grandchildren.

The museum gently discourages children under five, but only because they're so hard to control; all other youngsters are welcome. "We deal only in truth here," as a staffer said. "Truth is particularly appropriate for children."

In the Armed Forces Institute of Pathology, on the grounds of the Walter Reed Army Medical Center, 6825 16th St. NW. Open 9:30 to 5 daily, noon to 5 weekends; free. 576-2341 or 576-2418. CONFEDERATE MEMORIAL HALL -- What was for many years a haven of Confederate Veterans and their descendants has just become Washington's newest museum. Open to the public for the first time this weekend, the Confederate Memorial Hall offers a look into a long-gone way of life and a sense of the continuing vigor of the Southern tradition.

The Hall is "dedicated to the preservation of the best of Southern culture," says curator George P. Carroll. "It's a matter of appreciating the past, rather than clinging to it." Carroll, who started work on the 1870s townhouse only a few months ago, is more or less inventing the museum as he goes along. "We've been opening some doors that apparently had been closed since the last active veteran fell away around 1940. We haven't even got it catalogued yet."

Among the things he has discovered are Jeff Davis's bail bond, minutes of wonderfully contentious veterans' the eastern flank of the Great Valley. As the site of John Brown's pitiful slave insurrection on the eve of the Civil War, it took on symbolic importance over and beyond its considerable strategic value as a gateway on the North-South border and the chokepoint of the Baltimore & Ohio Railroad, which fed the Union cause with an endless stream of fighting men, food and fodder.

Union and Confederate troops fought over and through the town more or less constantly. By war's end the place was so downtrodden and thoroughly trashed that it never became the great transportation center its geography would seem to dictate. Progress passed by on t'other side, and the townsfolk neglected to tear down their historic buildings, twoscore of which have now been restored. Most of the old town center is federal property, and all of it is interesting, including the emporiums of the schlockmeisters.

Take U.S. 340 west from Frederick, Maryland, or Virginia Route 9 north from Leesburg, and follow the signs to the National Park Service visitor center. Open 8 to 5 daily; free. 304/535-6371, ext. 6222. SHEPHERDSTOWN -- The old Entler Hotel stands at the corner of German and Princess streets in this old Potomac River town, and has stood there since 1786 in spite of everything war and weather could do. Half of the restored building has become a community center; the other wing is the fledgling Shepherdstown Museum, which besides Civil War weapons and memorabilia has everything from a 1795 store ledger to a particularly fine pre-Revolution Sheetz rifle. There's also one of the first horse-drawn mail carts (the hotel was also the first federal post office in what became West Virginia).

The museum's open 11 to 5 Saturday and 1 to 5 Sunday. It's free (donations are gratefully accepted). To arrange weekday tours of the museum or the town, call director Terry Farrior, 304/876-2435. PENNSYLVANIA CARLISLE BARRACKS -- The U.S. Army Military History Institute in Carlisle, a town better known for the Washington Redskins' summer camp, maintains two public historical centers in a 1777 building here: the Hessian Powder Magazine Museum, chronicling the long and colorful history of this frontier army post; and the Omar (rhymes with Homer) N. Bradley Museum, with memorabilia of our last five-star general that include flags and guns that went with him through the North Africa campaign and the crusade in Europe, and medals and honors he brought back. The museum hours are meager and confusing, however:

To get to Carlisle Barracks, take Pennsylvania Route 34 north from Gettysburg and follow the signs. It's not a main road, but it's a nice one, and takes you through such hamlets as Floradale and Idaville.

The Bradley Museum is open 8 to 12 on Monday and 1 to 4 on Wednesday and Friday. The Hessian's open 1 to 4:30 on weekends and holidays. Both free. 717/245-3152. GETTYSBURG NATIONAL MILITARY PARK -- Fortunately for succeeding generations, the Rosensteel family amassed 30,000 Civil War items, most of them collected from the Gettysburg battlefields. More fortunately still, that collection wound up in the public domain, secure from the commercialism that has made the battle the town's principal industry.

Gettysburg has private and/or commercial museums and attractions to suit every taste, but the park visitor center, on U.S. 15 Business Route on the south edge of town, is the museum. Admission is free, but the electric battle map exhibit -- which everyone ought to see at least once -- costs $1.50 for persons 16 to 61, $1 for age 62 and up (kids up to 15 are free). Next door is the Cyclorama building housing Philippoteaux's vast and recently restored painting of the climax of Pickett's Charge, which everyone should see every time they go to Gettysburg. It costs $1 for persons over 15.

Open 8 to 5 daily, 8 to 6 from Memorial Day to Labor Day. 717/334-1124. -- Hank Burchard. Yankees, until I remembered I am one." "Stonewall's Valley" gives a stirring account of General Jackson's career, but scants the deeper question of how this eccentric VMI professor, mocked by the boys to whom he tried to teach math, metamorphosed into one of the finest, fiercest field commanders in history. As in the case of Patton, the answer appears to be that he was crazy, but foxy.

The hall is just off I-81's New Market exit. Open 9 to 5 daily; adults $3; children 7-13, 75 cents. 703/740-3101. WINCHESTER STONEWALL JACKSON'S HEADQUARTERS -- The town of Winchester changed hands so many times during the Civil War -- the official count is 74 captures and recaptures, with five "serious" battles -- that it's a wonder there was anything left after the smoke cleared away. There was in fact plenty of the infrastructure left, and much of it is there still, to the delight of visitors; this is one heck of a nice place to visit even if you don't care for apples, whose perfume suffuses the town from the great cold-storage warehouses.

The chief attraction, for those even moderately interested in the War Between the States, is the 1854 Hudson River Gothic Revival house that served as Gen. Thomas Jonathan Jackson's headquarters in 1861-62. It was from here that he launched the brilliant Shenandoah Valley Campaign, in which he marched his "foot cavalry" faster and farther than anyone but the fanatical Jackson would have believed any troops could endure, and several times whipped several times his weight in Yankees. It won him a permanent page in military history, and left him ranked second only to Robert E. Lee in the pantheon of Southern Saints.

Jackson's quirks bordered on the bizarre: He ate a weird diet and would ride for hours with an arm held high to keep his precious bodily fluids in balance. His habit of having himself frequently dashed with cold water, continued after the amputation of his arm, may have contributed to the pneumonia and pleurisy that carried him off.

His headquarters is virtually unaltered, and contains such relics as a lock of Jackson's hair, his prayerbook, cufflinks made from the brass buttons from his coat, and his rusty saber. The guide says it was already rusty when Jackson fell at Chancellorsville, that the general purposely neglected the weapon "because he said he'd rather have it rusted in the sheath than stained with any man's blood." Well, maybe so, but Jackson once scolded his men for holding their fire against a conspicuously gallant Union officer. You must kill the brave ones especially, he said, so the rest would run away.

Other mementos in the museum include Gen. Turner Ashby's saddle, perhaps the very one that the dashing cavalry officer was shot out of, and a tooth and a legbone from his horse. Yes. There's also a death portrait of Ashby: According to the custom of the time, his body was propped up and photographed for his loved ones. Also recognized in the museum is the unsung staff officer Jed Hotchkiss, whose meticulous maps Jackson said were the main thing that made the Valley Campaign possible.

The museum staff's enthusiasm is infectious, and if you don't watch out they'll sell you some genuine Suthrun war bonds and notes (you should have saved your Confederate money, boys, it's going for way over par). And it's hard to resist mentioning that the original owner of the house was Confederate Lt. Col. Lewis Tilghman Moore, great-grandfather of actress Mary Tyler Moore.

The museum's on Loudoun Street above Piccadilly; if you get to the gorgeous city library, you've gone just too far enugh (go in and look around before you turn around). Open 10 to 5 daily, April through October. Admission $3, $1 children over 11. "That's a one-time charge," the manager says. "If you've paid your way in here once, you're paid up forever." 703/667-3242. WEST VIRGINIA HARPERS FERRY NATIONAL HISTORICAL PARK -- Harpers Ferry is where the Potomac and the Shenandoah join forces to break through the Blue Ridge Mountains on Fort Lee, off East Washington Street, Petersburg. Open 8 to 5 Monday through Friday, 11 to 5 weekends and holidays; free. 804/734-1854. PETERSBURG SIEGE MUSEUM -- The city has made the 1839 Wheat Grain Exchange Building into an appropriate and affecting memorial to the citizens and soldiers who endured the hunger and disease (and, not least, the boredom) of siege. It's told mostly at first-hand, through diaries, letters and memoirs, with wonderful examples of such things as the tireless ingenuity of a man who wants something that tastes like hot coffee when there's not a coffee bean in town. The museum's film presentation is narrated by actor Joseph Cotten, a Petersburger whose voice training never entirely overrode his rich native accent.

At 15 West Bank St. Open 9 to 5 Monday through Saturday; $1 adults, 50 cents children. 804/733-2402. BLANDFORD CHURCH -- It's reason enough to visit Blandford Church that it has stood since 1735, or that 30,000 Confederate soldiers lie in its graveyard. But what draws most visitors is the Tiffany stained-glass windows. One was commissioned by each of the Confederate states, plus Maryland and Missouri, and one was done and donated by Charles L. Tiffany himself. The modest church, churchyard and attached interpretive center create the sense of solemn peace associated with great cathedrals.

At 321 South Crater Rd. Open 9 to 5 Monday through Saturday and 12:30 to 5 Sunday from Memorial Day through Labor Day; winter hours vary. Admission $1, 50 cents seniors and children. 804/733-2402. VIOLET BANK CIVIL WAR MUSEUM -- The members of the Dixie Artillery of the North-South Skirmish Association, out of the goodness of their hearts and the depth of their enthusiasm for all matters pertaining to the Civil War, maintain this 1815 plantation house -- which was Lee's headquarters for much of the Siege of Petersburg -- as a showplace of military arms, equipment and memorabilia such as an autographed portrait of Stonewall Jackson.

It is charming, but the giant "cucumber tree" (Magnolia acuminata) outside is nothing less than magnificent; it may have been planted as a seedling brought back from a mountain expedition about 1718. Or, if you prefer the romantic version, it grew from a switch that took root after a suitor stuck it in the ground.

Violet Bank is a block off U.S. 301 in Colonial Heights, a community just north of Petersburg's city limits. Open 10 to 3 Monday, Tuesday, Wednesday, Friday and Saturday, and 1 to 5 Sunday, from April 1 through October 31; free. SHENANDOAH VALLEY WARREN RIFLES CONFEDERATE MUSEUM -- It's "The War Between the States," thank you, at this engaging museum maintained by the United Daughters of the Confederacy. The Warren Rifles was one of the most dashing and romantic of the many local units that answered the call to the colors, and a number of the men's descendants have donated their flags, weapons, uniforms and letters. There's even an autographed photograph of the famous spy Belle Boyd.

At 95 Chester St. Open April 15 through November 1 (and at other times by appointment). Hours: 9 to 5 Monday through Saturday, 1 to 5 Sunday. Admission $1; children under 12 enter free but must be accompanied by an adult.NEW MARKET BATTLEFIELD PARK -- There are a few places remaining in the South where "the Woah" still goes on, and this is one of them. The Battle of New Market on May 15, 1864, was little more than a skirmish, but it featured a headlong charge by 247 young cadets from the Virginia Military Institute that turned the tide for the outnumbered Confederates. A quarter of the lads were wounded, and ten of them died; the Hall of Valor on the battlefield memorializes them, and the boys' names still are read at roll call at VMI.

The exhibits in the hall are outstanding, but the real, unreconstructed flavor is to be found in the films. "New Market -- A Field of Honor" recreates the battle in such stirring fashion that one visitor commented, "I wanted to grab a gun and go after those damn designed to carry frogmen equipped with limpet mines to within swimming distance of enemy ships. Looming above them all is the Intelligent Whale, an experimental craft of the Civil War era that may have had more sense than those who sailed in her. The new museum has another couple of hundred feet of expansion space, which is gladsome news to Navy museum fans. The museum's also shopping around for a retired submarine to moor alongside USS Barry.

Open 10 to 5 weekends, 9 to 5 weekdays; free. USS BARRY -- The decommissioned DD 933 is permanently docked at the Navy Yard, with her decks, bridge, galley and just about everything but the engineering spaces open to visitors. The 1956-vintage destroyer is manned by a host of helpful -- and knowledgeable -- young sailors who are happy to chat with visitors because, as one said, "It sure beats chipping and painting, Sir, which is what I'd be doing otherwise." It is striking, when striding her 424-foot length, to reflect that the Barry is a small warship.

Open 10 to 5 daily; free. 433-3377. U.S MARINE CORPS MUSEUM -- As might be expected, the Marines' museum is both smaller and rather more disciplined than its Navy counterpart, with many of the most venerated relics of the Corps displayed in neatly aligned and squared-away cases.

The emphasis is on the early days, when we could send out "a few good men" to quell a troublesome nation or create a friendly one, according to what seemed at the moment to be our manifest destiny. The layout is quite smartly done, especially the dioramas, and the trim young men who pull guard duty here are always willing and usually able to tell you anything you want to know about the history and mission of the United States Marine Corps, Sir!

Open 10 to 4 Monday through Saturday, 12 to 5 Sunday; free. In summer the museum reopens from 6 to 8 p.m. on Friday. 433-3534. MARYLAND ABERDEEN PROVING GROUND -- The U.S. Army Ordnance Museum has the right stuff, and lots of it. Parked all around the building are acres and acres of armored vehicles, including tanks and self-propelled guns captured in the world wars, Korea and Vietnam, some of which bear combat scars.

Enemy weapons -- and often those of our allies -- are brought to Aberdeen to find out what they can do and how to keep them from doing it to our guys. The museum is packed with displays that show how weapons are designed, developed and tested, and how and why they work. Many of the displays are masterpieces of the explicator's art, introducing laymen to the arcana of weaponry. There are also many small arms -- ours and theirs -- and outstanding historical pieces such as the command car General Patton used to chase Pancho Villa.

Signs show the way to the proving ground from I-95 north of Baltimore. The armor park's open during daylight; museum hours are 10 to 4:45 weekends, 12 to 4:45 Tuesday through Friday; free. 301/278-3602 U.S. NAVAL ACADEMY MUSEUM -- Annapolis is the heart of the Navy, and when the black-shoe Old Boys bring back a battle trophy or make out their wills, the Academy Museum often is uppermost in their minds. The museum also has a major teaching function, steeping midshipmen in the history and traditions of the service. Pacifists curious about the other camp might profitably spend an afternoon here: It may not fully explain why so many men -- and quite a few women -- love the profession of arms, but it certainly shows how they love it.

On the academy campus. Open 9 to 5 Monday through Saturday, 11 to 5 Sunday; free. 301/267-2108. FORT McHENRY NATIONAL MONUMENT AND HISTORIC SHRINE -- Our British friends wonder why we make such a fuss over the Battle of Baltimore, which was a relatively minor action even by the standards of the relatively minor War of 1812. What the British sent was a punitive expedition, not an invasion force. What happened was, they didn't capture Fort McHenry, but then they didn't try all that hard; and we captured one of their drinking songs, which, with stirring new words by Francis Scott Key, became our national anthem. It is a wonder that we survived attack by troops that could carry that tune while drinking.

Fort McHenry has been meticulously preserved as the city grew up around it, and now is an urban oasis that would draw crowds even if it didn't have an excellent museum and self-guiding tours of the batteries and barracks.

The fort's a straight shot from I-95 now that the new Fort McHenry tunnel's open. Take the Key Boulevard exit and follow the signs about two miles. Open 8 to 5 daily, 8 to 8 daily from June 13 Memorial Day through Labor Day; free. 301/962-4290. STAR-SPANGLED BANNER FLAG HOUSE & 1812 MUSEUM -- There's much to be said for private preservation of public treasures, and a prime example is the nonprofit society that maintains the 1793 Mary Pickersgill House, where the huge Fort McHenry flag was made. While the government cannot be said to have compensated Goodwoman Pickersgill very handsomely for her efforts, she of course became forever famous as the maker of the Star-Spangled Banner.

At 844 East Pratt St., near the Inner Harbor. Open 10 to 4 Monday through Saturday, 1 to 4 Sunday. Adults $1.50, seniors and children 13-18 $1, children 6-12 50 cents. 301/837-1793. USS CONSTELLATION -- The expression "iron men in wooden ships" takes on real meaning when one crouches on the gun deck of Constellation and reflects that the epitome of fighting seamanship was for her captain to lay the frigate right up against an enemy vessel, muzzle to muzzle, and see which ship blew up or sank first.

Built in Baltimore in 1797 as the first commissioned ship of the U.S. Navy, she soon claimed the first enemy man-o'-war ever to fall to our fleet, overtaking and capturing France's fastest fighting ship. Constellation remained on the Navy list for a century, first as a fighter, then as a training vessel and finally as a ceremonial flagship of World War II. Nearing the end of her second century, Constellation is under constant maintenance against all the ills that wooden ships are heir to, and the sections under repair are perhaps the most interesting parts of the tour.

Owned by a very nonprofit foundation, she's berthed at the foot of Pratt Street in Baltimore's Inner Harbor. Open from 10 to as late as 8 in midsummer; admission $1.75 adults, $1 seniors, 75 cents for children 6 to 15. 301/539-1797. USS TORSK -- Those who go down under the sea in subs are a special breed indeed, especially the men who served in such reeking diesel sausage tins as the fishy-named WWII fleet submarines (the torsk is a member of the cod family). After negotiating the boat's tortuous passages, one comes away marveling as over medieval suits of armor: Men actually stuffed themselves into things like this and went to war.

Attached to the Baltimore Maritime Museum in the Inner Harbor, Torsk is open 10 to 5 daily, 10 to 8 in summer; $2.50 adults, $2 seniors, $1 children 5 to 12. 301/396-3854. NAVAL AIR TEST & EVALUATION MUSEUM -- The early flying machines looked like machines that just might be able to fly, but take a close look at one of today's jet fighters and a small inner voice will whisper, "That can't get off the ground." Actually they don't, sometimes. The mission of NATEM, as the air test center calls itself, is to make sure an aircraft meets Navy specifications before it is accepted for issuance to the fleet. "The idea is to build planes that will make holes in the enemy and not in the water," as one visiting pilot told his young son.

There's some wonderful hardware here, including such failed experiments as an inflatable scout plane and a remote-controlled sub-hunting helicopter.

The museum, jointly operated by the Navy and the community, is at Maryland Rt. 234 and Shangri-la drive in Lexington Park, near the north gate of Patuxent Naval Air Station. Open 11 to 5 Tuesday through Saturday, noon to 5 Sunday; free. 301/863-7418. FORT MEADE ARMY MUSEUM -- Our Army is a sprawling and curious organism, made up of lesser armies which, partly for administrative reasons and partly simply by custom, are distributed geographically. Ours is the First U.S. Army Area (there's a separate Military District of Washington), and Fort Meade is its headquarters. First Army has a long and distinguished record, but did not actually, as its museum might seem to suggest, win both world wars by itself. The collection embraces uniforms, weapons, gear and memorabilia from the Revolution on. At 4674 Griffin Ave. on the post. Open 11 to 4 Tuesday through Saturday, 1 to 4 Sunday; free. 301/677-6966. FORT WASHINGTON PARK -- We built Fort Washington after our dismal experience in the War of 1812, and it worked: The British fleet has never again succeeded in capturing Alexandria. The fort's museum is not large, but it's largely successful in evoking garrison duty in an installation that, while it never fired a shot in anger, has long been a Potomac landmark. The magazines and bombproofs are cool in the heat of summer, and the park grounds are one of suburban Maryland's favorite picnic spots.

On Fort Washington Road off Indianhead Highway. Open 7:30 a.m. to dark daily; free. 763-4600. ANTIETAM NATIONAL BATTLEFIELD -- There are those who say that Antietam was the real turning point of the Civil War, and that Gettysburg just underscored the point that had been made here the previous fall: The Southern army could neither drive the Yankees out of the South nor successfully carry the fight to the North, so that the collapse of the Confederacy was simply a matter of time.

Be that as it may, these rolling cornfields and patchy woods saw the bloodiest single day of battle in which Americans have ever fought: September 17, 1862, during which 26,000 men fell. If the Union had had a fighting commander on the field, Lee and his widely scattered army might very well have been destroyed in detail, because the complete Confederate marching orders had fallen into Yankee hands.

The visitor center museum clarifies the tangled and horrific battle, and may have the most knowledgeable staff of any of the federal military parks in our region: They can tell you where almost any given unit -- sometimes even a given squad -- of either army was at almost any moment of the battle, and what became of it.

Off alternate U.S. 40 west of Frederick. Open 8:30 to 5 daily, 8 to 6 Memorial Day through Labor Day; free. 301/432-5124. FORT FREDERICK STATE PARK -- The sweetly sulphurous reek of black powder still hangs over Fort Frederick. The park has become a focal point of the revival of interest in early firearms, and on many summer weekends Fort Frederick booms with muzzle-loader enthusiasts dressed in authentic costumes, their faces streaked with authentic black-powder smudges. Early firearms also are on display in the museum, along with Indian artifacts and items associated with the fort's active years.

At Big Pool (of the Potomac), on Maryland Rte. 56 off I-70 west of Hagerstown. Open 8 a.m. to 10 p.m. daily; free, except for $3-per-car fee on special-event days. 301/842-2155. VIRGINIA ARLINGTON OLD GUARD MUSEUM -- The 3d United States Infantry Regiment knows it is the oldest and asserts it is the proudest of all the Army's active infantry units. Formed in 1784 after the disbandment of the Continental Army, the 3d has collected so many battle streamers that it takes a tough trooper to bear the standard: War of 1812; Mexican War (the regiment became known as "The Old Guard" after some brave and bloody work at Cerro Gordo); the Indian Wars throughout the 19th century (the 3d fired the final shot of those dolorous campaigns, against Chippewas under Chief Old Bug at the Battle of Leech Lake, Minnesota, on October 5, 1898); the Civil War, from Bull Run to Appamattox (including suppression of the New York draft riots); the Spanish-American War; the Philippine Insurrection; World War II and Vietnam. (World War I and Korea? Somebody has to stay home and train troops.)

Housed in a historic Fort Myer barrack, the museum is a trove of trophies and historic weapons, plus such startling artifacts as canned condensed milk from the Civil War. The museum's opening its second decade with a major expansion project (which will not interfere with visiting hours).

In its role as the Army's principal ceremonial unit (it's also combat-ready) the 3d maintains the Army's last mounted outfit, the Caisson Platoon , whose stables and equipment are open to the public. Also, along with its round-the-clock guard mount at the Tomb of the Unknown Soldier, the unit maintains the Trophy Room in Arlington National Cemetery's adjoining amphitheater, containing the honors and decorations bestowed by allied nations upon our unknown soldiers of both world wars, Korea and Vietnam.

The Old Guard Museum (696-3633) is open 9 to 4 Monday through Saturday. The Caisson Platoon (696-3568) hours are 12 to 4 daily. Both are reached by entering Henry Gate, on Arlington Boulevard (U.S. 50) at Pershing Drive. The Tomb of the Unknowns Trophy Room hours are the same as the cemetery's, 8 to 7 from April through September and 8 to 5 the rest of the year. To arrange for group tours or obtain further information, call the Old Guard information office, 696-3147 or 3148; free. ALEXANDRIA FORT WARD MUSEUM AND HISTORIC SITE -- Fort Ward was one of the largest and strongest links in the chain of 68 strongpoints that ringed Washington during the Civil War, which is why it was never attacked. The City of Alexandria launched the Fort Ward Museum in 1964; the staff and volunteers have since the beginning demonstrated that energy and scholarship can overcome severely limited funds to create a first-rate museum.

Through March 1987 the principal exhibition will be wartime paintings, sketches and sculpture, professional and amateur, that focus on the "common" soldier, whose artistry with, say, a penknife and a beefbone could be astonishing. If your curiosity is piqued by one of the exhibits, there's a 2,000-volume Civil War library plus a manuscript collection, and a reading room where they'll help you pursue a point to your head's content.

At 4301 West Braddock Rd., near the Route 7 exit from I-95. Open 9 to 5 Tuesday through Saturday, noon to 5 Sunday. 838-4848; free. FAIRFAX U.S. ARMY ENGINEER MUSEUM -- The engineers are the army's builders, and although they go armed they'd rather use their strong arms to keep the rest of the army going. It's a proud service (Robert E. Lee was a U.S. Army engineer), and this small but carefully crafted (of course) museum shows it.

At 16th and Belvoir, on the Fort Belvoir grounds. Open 10 to 4:30 Wednesday through Friday, noon to 4:30 Saturday; free. 664-6104. MANASSAS MANASSAS NATIONAL BATTLEFIELD PARK -- Two major battles were fought over essentially the same ground at Manassas, and for essentially the same reason: It was a key junction of a major railroad network. Both battles are classic cases of the fortunes -- and misfortunes -- of war.

The North, launching an enthusiastic but untrained army toward Richmond, nearly won the first one, on July 21, 1861. A strong drive around the Confederate left was slowed by T.J. Jackson's immovability (he became "Stonewall" Jackson here) and confusion over a blue-clad Confederate column that overwhelmed the Yankee artillery. Fresh Southern troops, arriving by train, drove the Union from the field, and though 'twas a famous victory, it wasn't the wild rout of legend. Most of the federal troops retired in good order, with effective rearguards, and the Confederates were too whipped down to follow them up.

Just over a year later, in August 1862, Union General John Pope played a deadly earnest chess game with Bobby Lee all over central and northern Virginia for almost a month. Lee had only recently taken command of the Army of Northern Virginia, and early on Pope established what looked like a winning position. But Pope, bedeviled by intrigues behind his back as well as Rebels on his flanks and rear, lost sight of one of Lee's major pieces, "Bishop" Longstreet. At the end of August Lee swept the Union army from the board in what became known as Second Manassas (the Union army called the battles First and Second Bull Run, but to the victor belongs the nomenclature). The federal troops withdrew to Washington, and Lee launched his first invasion of the north, which was to come to grief only a few weeks later at Antietam.

The Manassas visitor center, on Sudley Road (Virginia Route 234) just off I-66, is rather small for such a large park (3,200 acres), but the slide show, coordinated with a detailed electrified model of the terrain, makes the courses of the battles remarkably clear. Open 8:30 to 5 weekdays, 8:30 to 6 weekends; free. 703/754-7107. CULPEPER CULPEPER CAVALRY MUSEUM -- On June 9, 1863, Lee's army was sorting itself out for a march that would begin the next morning and end at Gettysburg. Jeb Stuart's cavalry lay at Brandy Station on the Orange & Alexandria Railroad, near Culpeper, when a slightly larger Union cavalry force under Pleasonton attacked.

Stuart was mortified, since to be taken by surprise is the penultimate sin for a cavalry commander. With 10,000 sabers on a side, it was the largest cavalry clash in the history of the Americas, and it went on all day. Eventually Southern reinforcements began to turn the tide, and Pleasonton withdrew, his mission accomplished: He had discovered that the Rebels were out in force and under marching orders.

In the following weeks the peacock-proud Stuart, still stinging from his embarrassment, tried to regain face by a wild ride around the rear of the Yankee army, and in so doing committed the cavalryman's ultimate sin: He left his commander wandering blindly in enemy territory, so that Marse Robert stumbled into battle on inferior ground at Gettysburg.

The broad plains around Brandy Station were littered with the wrack of war, much of which was gathered up by local residents, whose descendants long have treasured these weapons, photographs, diaries and other memorabilia. Many of the items now repose in the nonprofit Culpeper Cavalry Museum at Main and Davis streets in the center of town. Although small, it's a gem whose displays include videotapes made during local Civil War reenactments.

It's open from 9 to 4:30 weekdays, and is hoping to sign up enough volunteers to begin weekend hours. If they succeed, someone will answer 703/433-2318 on weekends; free. QUANTICO U.S. MARINE CORPS AVIATION MUSEUM -- Before they went on display in the Marine museum, these great old fighter planes were restored to flyable condition, and went through preflight procedures and even taxiing toward takeoff, because that's the standard here. They don't actually fly 'em for fear of pranging irreplaceable aircraft.

"We're not showing a replica of a Hellcat fighter, or the shell of one, we're showing visitors a Hellcat, and that means one with all its parts in working order," a curator said. Because it's housed in a historic but essentially unheatable early hangar building, the museum's open only in the mild months. Outside, there's artillery and armor, including a Russian T-34 tank captured in Michigan. Well, actually, made in Michigan, for shipment to the Russians during World War II, when anybody who was an enemy of Hitler's was a friend of ours.

The museum is on post at Quantico; a sign marks the right I-95 exit to use. Open from April through November, 10 to 5, Tuesday through Sunday; free. 703/640-2606. FOUR BATTLEFIELDS FREDERICKSBURG/SPOTSYLVANIA NATIONAL MILITARY PARK -- The four major battlefields of Fredericksburg, Chancellorsville, The Wilderness and Spotsylvania Court House, plus two historic buildings, have been synthesized into a single park by some administrative legerdemain that makes sense only to the National Park Service. The superintendent's office is in Fredericksburg: 703/373-4461. The six park units: Fredericksburg -- (Summer hours 8:30 to 6:30) Robert E. Lee thought the Yankees would be licking their wounds all winter after the carnage of Antietam, but Ambrose Burnside fooled Lee by moving the federal army to the banks of the Rappahannock opposite Fredericksburg within a matter of weeks. But then Burnside fooled around for nearly a month waiting for his engineers to bring up pontoons to bridge the river, although he could have ferried his army across on improvised rafts before Lee arrived in force.

Having lost the moment, Burnside proceeded, on December 13, 1862, to lose the battle and the best part of his army, sending brigade after brigade across open, rising ground to be slaughtered by entrenched Confederates and ranked batteries of cannon. It went on all day. Lee, watching his enemies melt away, said to an aide: "It is well that war is so terrible, lest we grow too fond of it." Burnside cried. Thousands and thousands and thousands of his men died. Then the cold cruel day darkened into a cruel cold night, during which many of the wounded froze to death on the field.

The Yankees fell back to Falmouth, and Richmond was safe for another winter. Much of the battlefield now is covered by houses, but the Sunken Road and Marye's Heights are still there and the visitor center museum makes the course of the action clear. The self-guided auto tour of the four battlefields, the Chatham headquarters/hospital and the Stonewall Jackson Shrine involves 17 stops and, depending on your choice of routes, may put 60 to 100 miles on your odometer. The visitor center, on Lafayette Boulevard at the Sunken Road, offers a free map and one that costs 25 cents; pay the quarter.

Open 9 to 5 daily; summer hours, 8:30 to 6:30; free. Chatham -- This 1771 Georgian mansion across the river from Fredericksburg served as a Union army headquarters and as a hospital where Clara Barton and Walt Whitman and other less celebrated volunteer nurses did their best for wounded and invalid soldiers. Chatham, considered one of the handsomest of Virginia's great houses, would be a notable attraction even without its historic associations. Follow William Street (Virginia Route 3) and the Park Service signs across the Rappahannock bridge.

Open 9 to 5 daily; free. Chancellorsville -- Come spring the Union Army, now commanded by "Fighting Joe" Hooker, marched upstream and forded the Rappahannock, fooling Lee again. But on May 2, 1863, Stonewall Jackson's "foot cavalry" marched nearly full circle around Hooker and smashed his right flank.

The Federal army well might have been destroyed, had not Jackson, Lee's darling "bad old man," been mistaken for the enemy and shot from his horse by his own troops while reconnoitering the front lines in the dark. Lee went on to whip the Yankees thoroughly, and sent them reeling back toward Washington. But without the help of the fierce and fanatic Jackson, who could drive troops like none other, Lee could not close the bag, and the Army of the Potomac limped away.

In truth Lee may be said to have suffered the greater loss at Chancellorsville, because on May 10 Thomas Jonathan Jackson, lying in a little outbuilding at Guinea Station, said, "Let us cross over the river, and rest in the shade of the trees," and died. With him went Lee's heart and his last, best hope; the loss of his finest commander could never be overcome.

Chancellorsville Battlefield and visitor center are on the Orange Turnpike (Virginia Route 3) west of Fredericksburg.

Open 9 top 5 daily; summer hours, 8:30 to 6:30; free. Stonewall Jackson Shrine -- The left arm of Lee's right-hand man was amputated at a battlefield hospital May 3, and next day he was taken 25 miles to Guinea Station, then as now a rural railroad hamlet, where he languished for a week at Fairfield Plantation before giving up the ghost. To get there, follow Virginia Route 208 south from Spotsylvania Court House and bear left on Virginia Route 606 at Snell. Or take 606 east from I-95's Thornburg exit.

Open 9 to 5 daily; free. The Wilderness -- This battle, fought in a hellish, endless undergrowth so thick that men could fight muzzle-to-muzzle without being able to see each other's faces, marked the beginning of the end for Bobby Lee and the Army of Northern Virginia. Now he was facing Sam Grant, who was headed for Richmond and was determined "to fight it out on this line if it takes all summer."

On May 5, 1864, Grant almost won the battle; next day Lee counterattacked -- through smoldering woods where wounded men lay screaming until they choked or burned to death -- and forced a draw. Any previous commander of the Army of the Potomac would have withdrawn, or dug in and howled for more men and supplies. Grant just sidestepped and raced on for Richmond, while Lee backpedaled furiously to shield the Confederate capital.

The battlefield and exhibit shelter lie west of Chancellorsville on Virginia Route 3. Although much of the land has been cleared for farms, much of the Wilderness still is wilderness. Relic hunters have gone over the ground (legally or otherwise) for more than a century, but a recent visitor, stumbling and thrashing through the thickets in an effort to get a sense of what the soldiers saw, came upon an unrecorded and undisturbed artillery emplacement.

The battlefield is open round the clock; a historian is on duty from 10 to 6 on weekends. Spotsylvania Court House -- By May 8 Lee was entrenched at this rural county seat and Grant was already pecking at him again. Then on the foggy morning of the 12th he launched an attack that swept through part of Lee's line. Both sides steadily sent in reinforcements in a twenty-hour fight, unmatched through the war for hand-to-hand savagery and prolonged horror, that became known as the Bloody Angle.

The slaughter bought Lee enough time to fall back and retrench. Grant kept hammering at Lee for more than a week, then withdrew from the field May 21. But if The Wilderness and Spotsylvania had hurt the federal army badly, it had hurt Lee too; and Grant's supplies and reinforcements were coming thicker and faster. Grant soon had his army on the march again, and it still was marching south. Lee, behind a screen of cavalry, again was furiously digging in. The battlefield lies on Brock Road (Virginia Route 613) south of The Wilderness.

The battlefield is open round the clock; a historian is on duty from 10 to 6 on weekends. RICHMOND COLD HARBOR -- This no-account crossroads, actually a mile of ground between two no-account crossroads on the eastern approaches to Richmond, was the armies' next meeting place, on June 3, and here a record for grim efficiency was set that endured until the era of the machine gun: In just half an hour of frontal assault against Lee's trenches, the Union lost 7,000 men. The blue-clad soldiers fell at the rate of four a second, like the curl and collapse of waves on the shore; with them died Grant's hopes of taking Richmond by storm. The Union commander acknowledged Cold Harbor as a terrible mistake, and never made such another. Grant sidestepped again, crossed the James River, and invested Petersburg, a key Rebel rail center.

Cold Harbor Battlefield and visitor center are on Virginia Route 156, easily reached from the Creighton Road (Virginia Route 615 east) exit of the I-295 bypass west of Richmond. The center's open 9 to 5, the battlefield 9 till dark; free. CHIMBORAZO VISITOR CENTER AND MUSEUM -- "We must stop this army of Grant's before he gets to the James," Lee had said. "If he gets there it will become a siege, and then it will be a mere matter of time." He was right, but it was a matter of 10 more months before Richmond and Petersburg fell.

Chimborazo, a federal and city park on the site of what is said to have been the largest hospital the world has ever seen, is the place to start a tour of Richmond's Civil War centers. Like the Southern battlefields, it has become federal property not by right of conquest but by conciliation, and the exhibits are the fruits of splendid and even-handed scholarship.

Richmond was triced up in a continuous belt of fortifications that stretched for 65 miles (plus inner works and fallback lines that make the complete auto tour amount to 100 miles). Manning them, and the Petersburg trenches to the south, kept both armies busy but essentially immobilized. Which worked steadily to Grant's benefit, because whenever Lee wasn't winning, he was losing: Grant had him in a stranglehold, and time could only work against the Southern cause.

Chimborazo Center is at 3215 East Broad St., Richmond. Open 9 to 5 daily; free. 804/226-1981. MUSEUM OF THE CONFEDERACY -- There was a time, not all that long ago, when merely raising a question about the generalship of any Southern commander would have been received in Richmond as heresy if not treason: They were all heroes, and that was that.

Now, in the very temple of the Confederacy, there is an exhibit that speaks frankly of "the Braxton Bragg problem," which was, simply, that he was a second-rate general who frittered away the Army of Tennessee, many of whose surviving soldiers gave up in disgust and went home. This revisionism is as refreshing as the museum's collection is outstanding, and an ongoing refurbishing of the building and exhibits promises to make the place even more irresistible.

At 1201 East Clay St. Open 10 to 5 Monday through Saturday, 1 to 5 Sunday; admission $2.50 adults, $2 seniors, $1 children 7 through 12. The same admission is good for the adjacent White House of the Confederacy, where Jeff Davis' dream died and his four-year-old son was killed in a fall, but it is undergoing major renovations and may or may not be open on any given day. 804/649-1861. PETERSBURG PETERSBURG NATIONAL BATTLEFIELD -- Grant had Lee like a scorpion in a bottle, certain that dwindling supplies and mounting frustration would force him either to offer battle or abandon Richmond and Petersburg. And so it happened, in April 1865, after the Yankees captured the Weldon Railroad, cutting the last major Southern supply route. In one of the endless ironies that marked the war, it was the retreating Rebels who torched and looted the towns and the Yankees who fought the fires and restored order.

The Siege of Petersburg, which was less dramatic but just as pivotal as any battle -- and cost 70,000 casualties -- is highlighted by the Battle of the Crater. Union sappers dug a 500-foot tunnel to a spot under the Confederate lines, packed it with four tons of gunpowder and blew away a whole segment of the defenses. But after the blast, which was the greatest man-made explosion up to that time, everyone including the Yankee assault troops moved in a slow-motion daze. The Southerners recovered their wits first, and their counterattack became a frenzied butchering of Union troops.

A walking tour of the Petersburg defense lines is equally likely to be accompanied by the evocative sounds of marching men on adjacent Fort Lee or the mood-destroying racket of boom boxes played by young people who have seized much of the high ground for partying.

The Petersburg Battlefield exits are marked along I-95. Open 8 to 5 daily, 8 to 7 in midsummer; free. 804/732-3531. U.S. ARMY QUARTERMASTER CORPS MUSEUM -- Beans, bullets, bread, buttons, bacon, bandages, butter, bugles, belts, berets, bayonets, buns, buttplates, boots, bran, badges, batteries, brassards, brassieres . . . the quartermaster has to come up with everything, and generally he does, if you fill out the right form right.

The QM's got it all, and it seems like most of it's on display in this engrossing and cavernous temple to the service of supply. There are thousands of samples of genuine GI (Government Issue), from Civil War hardtack biscuits (perhaps not much staler now than when they were issued) to modern battlefield body armor. They've even got General Patton's air-horn-equipped jeep, for which the curatorial infighting must have been vicious. Appropriately enough, the place also has one of the best military museum shops you'll ever see.