The day is ending in Poplar Harbor, a lagoon surrounded by eroding, uninhabited islands in the heart of the Chesapeake Bay, and all around our anchored 28-foot sloop, the air is still, the water unctuous, the light ruddy.

The sun is hanging just above the bay's dark western shore 10 miles away. For a liquid, summer moment, the distant superstructure of a passing merchant ship is silhouetted in red. Then, some 200 yards off our port bow, the anchor light of the only other yacht to share the harbor with us this night suddenly twinkles.

I am standing barefoot on my sailboat's cabin top, barely 30 miles due east of Washington, but, with the lagoon gently nuzzling the hull, I am not thinking of anything in particular. I just know that the moment has come. I stretch out my sunburnt body to its fullest and dive, arcing high over the burnished water as day and night meet.

Sailing is a curious pastime -- half sport, half meditation, and you can switch from one to the other and back again and hardly realize it. If you're one of the growing numbers of people who have been smitten by sailing and the freedom it gives, you should consider yourself lucky. Because there are few places in this world as felicitous as the great Chesapeake Bay when it comes to sailing.

Consider the facts:

More than 200 miles long from the Chesapeake and Delaware Canal to the north to Norfolk in the south, its 4,600 miles of shoreline are ragged with coves, slashed by rivers great and small and lined with villages, towns and cities of all types and histories. Its waters teem with crab in the summer and wild fowl in the fall and winter.

When it comes to American history, there is no other body of water as rich, either. At all turns, the nation's roots clutch at its shores and tributaries: Jamestown, the first successful English settlement, up the James River; Yorktown, where the colonies won the right to be a nation, on the York. George Washington was born and died along the banks of the Potomac, while FDR supposedly used to visit the little island just to the stern of my sailboat in Poplar Harbor for high-level politicking.

Interested in racing? Some of the best sailboat racers and racing sailboats call the Chesapeake home.

But to me, the best thing about the bay is that I can still find solitude and beauty going hand in hand. This, despite the 200,000 or so boats registered in Maryland, Virginia and the District -- not all of which are on the bay, mind you.

And even when you find yourself sharing a little cove with another boat, chances are your neighbor at anchor feels just as you do about peace and quiet.

There's no arguing that the bay is becoming maddeningly crowded, particularly on weekends and especially near Annapolis, one of the world's sailboat capitals. Saturday morning in Annapolis is chaos, with scores of boats scrambling across the open waters for St. Michaels, the favorite Eastern Shore port, a pleasant sail across the bay.

And more and more often in the five years I've been sailing on the bay -- even on cloud-shrouded, rainy days -- I have found myself suddenly surrounded by wildly careering sailboats racing for some foggy port.

But all you have to do is wait a moment and they are soon swallowed by the mists. Then, as if by magic, the silence and solitude descend again.

Unquestionably, if it's space from your fellow man you seek, then the best time to sail on the bay is mid-week.

But there are special places where chances are good that you can find yourself with enough elbow room on the weekends to make it pleasant. Here are my favorite four, in no particular order, discovered over time. The first three are Eastern Shore anchorages, while the last is located near the mouth of the Patuxent an hour's drive from Washington.

* Poplar Harbor. Located six hours southeast of Annapolis, Poplar Harbor is just off the western shore of Tilghman Island. You enter the lagoon from the east side. On the islet that makes the northern edge of the harbor entrance is an old hunters' lodge with a long dock stretching into the shallow harbor. The island was recently purchased from the Smithsonian by a group of Washington-area residents who are restoring the lodge, where the likes of FDR supposedly met for Democratic powwows. It is, however, private property.

The harbor is fairly shallow -- about 5 1/2 to 6 feet deep. The entrance channel is even shallower; it can drop to 4 1/2 feet at low tide. But the bottom is soft so you can easily slide off if you nudge around.

Keep in mind that the harbor is not very well protected in a blow. About 20 minutes after the merchant ship slid past the island at sunset we felt our boat riding on big swells, apparently the wake of the boat, despite the fact that we were surrounded by what appeared to be a solid ring of sand dunes and marsh.

The water is warm, the view spectacular. Take your bug spray, however, for the evening mosquito attack.

* The Wye River. One sultry summer night when anchored in one of the many quiet creeks that edge Wye Island, I was awakened by the approach of the most spectacular thunderstorm I have ever seen. It sounded as if the Russian Front were nigh.

In the dead calm that preceded the storm, I watched the night sky and covered my ears as blinding explosions of lightning shattered the darkness. Abruptly, the wind gusted up from the stern with a mighty puff, shoving the boat straight ahead, right over the top of the anchor, leaving me to watch with horror as the dim shore rapidly receded. Would the anchor hold or would we find ourselves hard aground in a wild storm?

Smartly, the anchor held, swinging the boat around 180 degrees. But I can assure you it was a heart-thumping 10-second ride.

For sheer variety of quiet anchorages, Wye Island, around which the Wye River runs, is unmatched. It is also redolent with history.

Located on the Eastern Shore of Maryland, Wye Island was one of the first places settled by English colonists in the upper Chesapeake. Supposedly, the first wheat ever grown in North America was planted here. Its shaded creeks and dark waters seem to exude antiquity, as do the many old mansions along the Wye's banks.

In the fall, the Wye -- just north of St. Michaels at the end of the Eastern Bay -- is particularly stunning. Cool and quiet, its banks a visual symphony of reds and golds, it is filled with literally thousands of wild, migrating duck and geese. If you are very, very quiet, they may land and feed close by.

Ten or so years ago, a developer tried to make the island into a chic-chic vacation/weekend residential spot. Heavy local opposition, coupled with the ire of environmentalists, defeated the attempt. As a result, the island is virtually undeveloped and serves as a largely state-run agriculture testing site.

Watch the winding channels. They are shoaly and largely unmarked, but there is plenty of deep water if you keep to the middle.

* Casson Point. Last October, on a balmy Indian Summer night at anchor behind Casson Point, my wife and I lay for hours in the cockpit of our boat watching meteors streak across the sky.

Located up the Eastern Shore's Little Choptank River at the mouth of Hudson Creek, Casson Point is far enough from major cities to possess a night sky virtually unbesmirched by light pollution. It is also far enough away from Annapolis -- about 10 hours by sail -- to make it a good bet as an anchorage where you'll find wide-open spaces on a nonholiday weekend.

The point is scythelike, sweeping down from the north and around to the east, where it opens onto the Little Choptank. There are few visible dwellings, so the sense of isolation is nearly complete (although about four miles away, just on the other side of the Little Choptank, is the Taylors Island Coast Guard Station, one of several along the bay shores).

The entrance to Hudson Creek, which is the second inlet to the north after you enter the Little Choptank from the bay, is well marked -- I've waltzed into it with no problems at 3 a.m. Just round the final mark and point the bow into the middle of the bight formed by the point. You can anchor within about 60 yards of the point and feel secure. Just make sure the wind isn't expected to kick up heavily from the northeast that night, because you are not as well protected from that direction.

* St. Leonard Creek is a gem. Located on the western shore of the bay about an hour's sail up the Patuxent River past the bustling little harbor of Solomons Island, it offers just about everything you could want for a weekend. There are protected, private, deep-water coves; a dramatic, high-profile shoreline thick with trees; handsome old and new homes, and even a funky marina/restaurant far enough up creek to be out of sight and mind if you want it to be.

The creek has even found its place in our history books. The left-hand bluff as you enter, now a state park, appears to be the same spot marked on a chart by Capt. John Smith as the location of a large Indian village. State archeologists are excavating the area.

During the War of 1812, the creek mouth was also the site of a naval battle between the British navy and colonists aboard barges armed with small cannon. The Americans, holed up inside the creek, managed to drive off the British. But it was a Pyrrhic victory of sorts, since the British then sailed up the Patuxent and marched on Washington, burning the White House in the process. Locals say one of the American barges is sunk in the creek entrance somewhere.

St. Leonard is deep -- about 15 feet -- for the first mile or so and there is a lovely cove just to the left as you enter that has up to 7 feet all the way back to the very end. The green marker at the mouth marks the left-hand edge of the channel as you enter.

There is much beauty on the bay, but there is no reason to be complacent about it. This cove on St. Leonard Creek is a good example.

Located at the foot of the state park, it is one of the most beautiful and untouched coves on the entire bay. But the state is now trying to lure a major marine research operation to the park. Their plan? To build a dock onto the cove and use it as a base for their research vessels.

The issue is undecided -- there is significant local opposition. But it serves as a reminder that the peace and tranquility that is still, in many areas, the essence of the bay is under constant challenge -- even from those who believe they are protecting it. Don Nunes, a Washington Post reporter and editor for 11 years, is now The Post's marketing manager.