The Indians called the river Greasy Grass. It runs today, as it did a century ago, amid a grove of cottonwood trees and wild rose bushes, sheltered by a line of hills that rise to the east like a wrinkled, puzzled brow.

At noon or later, when the summer sun fills the big Montana sky and makes you squint through the haze and the dust at the river below, you can easily imagine the Indian camp of a hundred years ago: thousands of lodges that jammed the valley and sheltered as many as 15,000 Sioux and Cheyenne.

Squint harder, and you can forget the Burlington Railroad tracks that crawl along the valley at about the spot where the Seventh Cavalry first launched its attack, and ignore the highway culvert where Sitting Bull's Uncpapa Sioux first turned the bluecoats back.

It doesn't take much to envision the troopers as they climbed from their horses to set up a skirmish line, or to see them break and run, splashing across the Little Big Horn River, pursued by red-skinned warriors, and up the bluff toward where you stand.

You can almost hear the sound of battle: the hoofbeats of panicked horses, the frantic commands of officers, the staccato gunfire of Springfield rifles, the buzz of arrows -- the curses, prayers and frightened cries of Lt. Col. George Armstrong Custer's dying men.

Then close your eyes and listen to the silence -- to the rustle of box elder branches in the wind and the gurgle of water down below -- and imagine the scene as the battle ended: dead horses dotting the hillside, the bodies of soldiers lying in the sun, the victors riding away with guns and uniforms taken from the defeated foe.

A well-preserved battlefield can do that to you -- and, for now at least, the battlefield at Little Big Horn in southeast Montana remains in pristine condition: almost exactly as it was on June 25, 1876, the day of Custer's Last Stand.

I have always been a history buff -- not the kind that brings a metal detector to comb the ground for arrowheads or bullets, or elaborate maps to chart the advance of each battalion -- but if I'm passing the grounds at Wilderness or Bull Run, I seldom fail to take the time to wander through, reading the markers and letting my imagination ramble.

I get it from my mom, I guess. When my dad was away on business trips she'd pack us in the car and off we would go to see the bridge at Concord, the green at Lexington or the battlements at Yorktown. The genes did the rest.

Later, the presence of history helped lure me to the University of Virginia, and on many a spring night we would go "boondocking" with the girls from Mary Washington College -- winding down dark roads in the battlefield parks at Fredericksburg or Chancellorsville to build a fire by the river and slip "Baby I'm-a Want You" on the Mustang tape deck, hoping that the ghosts of the men who died at Bloody Angle might drive her closer into your arms.

Virginia is justifiably proud of its Civil War battlefields -- to a large extent they remain as they were -- but to my mind none can hold a candle to the field at Little Big Horn in re-creating the atmosphere of a century ago.

The Custer Battlefield National Monument, as it is formally known, remains well preserved. It is one of our youngest battle parks and perhaps the most isolated, and much of the field remains in the hands of the Crow Indians. The Sioux and Cheyenne may have carried the day, but the descendants of Custer's Crow scouts retained the land -- and their poverty has precluded any extensive commercial development.

It is here, on the flanks of the Wolf Mountains 65 miles southeast of Billings, that Custer and his 675 men descended on the people of Sitting Bull, Crazy Horse and Gall one hot summer day. To the Indians, it was the Moon When the Chokeberries Are Ripe (June). The Seventh Cavalry was just part of a massive U.S. force determined to herd the tribes back to their reservations. More than 900 books and a dozen Hollywood films have told the tale often enough: how Custer divided his command into three columns, sending Capt. Frederick Benteen to search for more Indians, ordering Maj. Marcus Reno to attack the southern end of the camp and taking 200 men along the bluffs to the north with the intention of surrounding his opponents.

Yet much of the allure of the battlefield is the mystery that still surrounds Custer's fate. There were no white survivors of the Last Stand, and Indian accounts vary. Was Custer killed early in the battle, throwing his command into turmoil? Or was he -- as several Indians testified later -- truly the last to fall? Did his men panic or fight bravely? Did any shoot themselves? Did they reach the river, meet a furious defense and retreat? Or were they surrounded on the bluffs and killed as they tried to consolidate their position?

The 200-odd white marble slabs that are scattered around the battlefield provide moving but inexact answers to where the troopers fell. The bodies of Custer's men were discovered two days after they died, and only the officers received anything approaching a burial -- the enlisted men were left exposed to the elements and scavengers, in many cases for years. The first true burial occurred in 1885; the markers were placed six years later.

Recent events now add to the story. In the summer of 1983 a prairie fire swept the five miles of bluffs, clearing the battlefield of dense underbrush and rattlesnakes and allowing archeologists to begin the first comprehensive excavation at the site.

For five weeks last spring an army of volunteers covered 600 acres around Last Stand Hill, unearthing more than 1,900 artifacts -- including hundreds of bullets and cartridges, the severed finger, complete with ring, of one trooper and the partial skeleton of another -- that were then plotted by a computer to reconstruct the probable flow of the battle.

The computer analysis convinced the archeologists that the Indians were far better armed than historians had thought. Criminologists from the Nebraska State Patrol examined the ballistics evidence and decided that there were from 117 to 350 guns in Indian hands -- and that the Last Stand was a short bloody war of attrition as the warriors picked off the troopers one by one, overwhelming the skirmish lines and driving the cavalry back to where a granite marker now marks their final stand.

The work -- by archeology teams from the National Park Service and the Custer Battlefield Historical and Museum Association, a private foundation -- grew in notoriety with the acclaimed publication, in late 1984, of Evan S. Connell's "Son of the Morning Star," a best-selling account of Custer and the battle.

The digs will continue this month, with new theories gaining prominence and old arguments reborn: What, for example, happened to the 28 men of E Company, whose bodies were not located where legend said they should be, beneath the twisty shores of Deer Ravine?

Custer's dying ground has always been popular -- attracting about 250,000 visitors a year -- but the digs boosted the tourist trade by a record-setting 50 percent last May when the work was under way, and the quota of 150 volunteers for this year's excavation (at the Reno-Benteen battlefield, where the two subalterns and their men held out some five miles from Last Stand Hill) was filled by last January.

While you can't wander aimlessly through the field -- the rattlesnake warnings alone will keep you on well-marked trails -- the park personnel promise this year to enhance their always splendid talks and demonstrations with up-to-the-minute reports from the archeologists.

The battlefield stretches from the grassy knoll at the southern end where Reno and Benteen withstood an Indian siege for two days, to where the granite monument atop Last Stand Hill marks the northern entrance to the park about five miles away. The battlefield guides are well versed in Custer lore, and their stories of individual bravery among the armies of both sides can send shivers down your spine.

Custer was found just a few feet to the south or southwest of where the monument stands now; he had been shot twice. He was not scalped, but according to tradition two southern Cheyenne women punctured his eardrums after death with a sewing awl so he would better hear warnings of danger in the next world.

Less than a tenth of the battlefield is federal property -- most of the rest belongs to the Crow, some of whom would like to develop the land to ease the economic pressure on their tribe. Congress has not been willing to purchase the entire field -- a sure case of historic short-sightedness -- and an effort by Last Stand aficionados to raise funds to buy the land progresses slowly, with no guarantee that the splendid vistas won't someday be marred by tract housing.

If that happens we will all be the poorer. But Custer's legend won't die with his battlefield.

As Connell puts it: "Even now, after a hundred years, his name alone will start an argument. More significant men of his time can be discussed without passion because they are inextricably woven into a tapestry of the past, but this hotspur refuses to die. He stands forever on that dusty Montana slope."