YOU COULD PROBABLY put a fence around the whole eastern half of Virginia and call it a historical park. Some 1,500 markers within Virginia's borders tie the early history of America to events that occurred in the commonwealth. Jamestown saw the first English settlers, Williamsburg the earliest stirrings of the Revolution. More than half the Civil War was fought on Virginia soil.

But it isn't just history that brought an estimated three billion tourist dollars into the state's coffers last year. Virginia offers some of America's loveliest natural attractions, from the smoky Blue Ridge Mountains to the sparkling sands of Virginia Beach.

European visitors, who have never been impressed by history not as old as many of their homes, have been swelling tourist figures recently because they love the splendors of Skyline Drive in spring and fall, the strange underground world of Luray and the imaginative play acting of Colonial Williamsburg.

For American tourists, all these delights are remarkably accessible. Virginia lies within a day's drive of half the U.S. population, so it's easy to come by car with the kids, and to combine a history lesson with a visit to theme parks, a beach holiday or a mountain camping trip.

The World's Fair in Knoxville is going to be a plus for Virginia tourism. The most direct route from most states will be via Interstate 81, and Marshal Murdaugh, who heads the Virginia State Travel Service, says this can hardly help but benefit the southwestern part of the state. Virginia is drawing increased interest from the international market, Commissioner Murdaugh said, and the state has been included in more tour packages from Switzerland and Germany.

In anticipation of another good season, the folks in the 10th original state have been readying new accommodations. In Richmond, there's a new bed & breakfast, Bensonhouse, while in Charlottesville the well-established Guest Houses Reservation Services is going strong. The Richmond Rehabilitation and Housing Authority will loan the Marriott Corp. $24 million toward a new 400-room Marriott to be built in Richmond's Project 1 area and scheduled for opening in 1984. The new Norfolk Hilton will be accepting guests by fall and the chain says its new venture will rival the long-dominant Omni.

Richmond's Jefferson Hotel, once the premier grande dame of the city, was to have been renovated and the famous alligator returned to the lobby, but funds for the project have been hard to come by. Plans for the hotel, which is closed at the moment, are up in the air due to high interest rates. Betty Dillehay, president of the new city booster organization, Richmond on the James, says definitely that the Jefferson will live again, but others are not so sure. "The amount required is incredible," says a knowledgeable source who did not wish to be named.

Sure to be a hit in the capital city is the renovated Raleigh, scheduled to be reborn this fall as a concierge-type hotel called the Commonwealth. Guests will be picked up at the airport, tea will be served in the afternoon, and an elaborate file of guests' preferences kept in anticipation of return visits.

No one expects the venerable Homestead in Hot Springs to feel the pinch of the economy, since it draws from a clientele which would be least apt to suffer, but the state's ski resorts this year are purposefully emphasizing their year-round appeal.

Wintergreen, for instance, doesn't want to you to forget that their Devil's Knob Mountain Golf Course is splendid in the summer, their Paul's Creek water slide offers fun when the snows are only a memory, their hiking trails and tennis courts are in their prime when skiing is not. On Wintergreen's calendar of events are things like a spring wildflower festival and a craft and music festival in August. They are also offering a fistful of package deals to attract spring and summer guests.

Almost 2 million people last year motored throught the Shenandoah National Park on that famed highway in the clouds called Skyline Drive, camping, hiking and enjoying a world preserved from the bulldozer. These figures were up more than 100,000 from the year before, with bumper-to-bumper traffic as usual when the leaves turned in October.

Traffic in May, however, is only a little more than half what it is in the fall, so that viewing the wild flowers and the dogwood this month can be especially pleasant. From the overlooks in the park you get a sense of the diversity of Virginia. Spread out like a diorama are the Blue Ridge and the Piedmont to the east and, to the west, the Alleghenies and the Shenandoah Valley. Within sight is Luray, which last year drew roughly a quarter million visitors.

Among man-made wonders, Colonial Williamsburg is probably Virginia's prime attraction, and attendance climbs every year until it seems there can't be a closet in America without a tricorn hat bought for the kids on a trip to the restoration. About 1.12 million visitors are expected this year, 10 percent of them Californians. Why Californians? "They're rootless," says Tom Schlesinger of the Colonial Williamsburg office, "and these are everybody's roots. It's part of the grand tour of the U.S." More than $1.5 million pours into Colonial Williamsburg every week but the restoration is advertising more frequently these days. They're well aware that discretionary income is getting harder to come by.

Virginia is the mother of presidents--you could spend a week or so just visiting the early homes of the FFV's (First Families of Virginia). Mount Vernon, Monticello, Ash Lawn, Berkeley, Woodrow Wilson's home in Staunton are big favorites, but there is no dearth of other great houses belonging to men who shaped the history of the country. Stratford, the Lee family home in Westmoreland County, Kendall Hall in Fredericksburg, Shirley Plantation in Charles City, all allow us 20th-century visitors a look at life in the grand mannerin the 18th century.

The Virginia state dog is the foxhound, and if you want to see the part of Virginia in which he is most important, Loudoun County is your destination. The stately homes here include Morven Park and Oatlands and, for a peek at the horsey life from the base up, tour the stables of Middleburg and Upperville when they are open this year, May 29 and 30.

At the southern tip of the Commonwealth, Virginia Beach, with its three miles of concrete boardwalk and 12 miles of some of the best kept beaches in the East, is the main draw. This is the home of the famous Lynnhaven oyster, an odds-on favorite at all the seafood restaurants. At Chincoteague, the oysters grown on the sandy bottom off shore are considered among the best in the East. Thousands gorge on them every year when they come to see the ponies rounded up from the barrier island of Assateague and made to swim the inlet for an auction.

Margaret Henry's book, "Misty of Chincoteague," has been bringing families there on the last Wednesday and Thursday of July for years. Come some other weekend and you can see the ponies peacefully grazing at the wildlife refuge on Assateague. (Bring your mosquito repellent.)

And then there are the theme parks, those purveyors of thrills and illusion, fast food and journeys into man-created adventurelands. Down by Colonial Williamsburg, the Old Country of Busch Gardens will be open every day beginning May 17 (weekends only now). The management has been touting the new show of Mark Wilson, magician at the Globe Theatre, who has boned up on some tricks once performed by Houdini and Thurston. Jaime the Chimp has assembled 14 costume changes for her cooking, painting and acrobat duties, and there's a new comic unicycle act called the Volantes.

Kings Dominion, 20 miles north of Richmond, will go daily June 3 (it's open weekends and also will be open May 31, but it's closed today). They've installed a new giant, double figure-eight roller coaster guaranteed to rattle your back molars. It goes through a dense forest and starts off with an eight-story drop as a warm up. Afterwards there's a dark, narrow tunnel and--well, you'll have to see for yourself . . .

A quarter of a million visitors last year found their way to Hampton to see NASA's Langley Visitor Center where more than 40 exhibits explore the challenge of flight. Plans for this year include updating of the gallery's very popular "Evolution of Aircraft" exhibit.

If your subconscious is dredging up Virginia more than usual lately, it may be because the commonwealth legislature has created a state film office to attract Hollywood to Virginia for movie locations. "Coalminer's Daughter," "Final Countdown," "Four Seasons," "Best Friend," all have Virginia settings. The upcoming BBC film, "Lady Astor," will be shot on Church Hill in Richmond. Films are the ultimate in publicity value and could well increase tourism.

Despite all the good news, the scramble is now on for the tourist dollar in the face of the recession. Virginia, banding together with North Carolina, South Carolina, Georgia and Florida, has a two-year promotional budget of $1.2 million to get her share. A hopeful development is the big increase in motor coach business, a fancy name for city-to-city bus tours. The Virginia Travel Council, a privately funded organization, met recently in Richmond with six bus companies and peripheral suppliers to consider what to do to encourage even more. "Something good's going to come of that," says Murdaugh.

It's a big state and, from the Port of Hampton throbbing with the world's shipping to the quiet battlefield of Appomattox, its attractions are as diverse as oil and water. And yet the state is knit by a strange tie, noticeable to outlanders, a common sense of what it means to be a Virginian. Graduates of its university refer to it as The University and have been known to come home from alien states in order that their children can be born on Virginia soil. Attendants at the Lee House in Alexandria report that a man not long ago burst into tears when he failed to trace his ancestry to the Lees of Virginia.

"Sic Semper Tyrannis," intones the state motto. "Virginia Is for Lovers," say the bumper stickers. Could be Virginia is for anyone with a little romance in his soul.