an impressive name to live up to. And for the past 10 years it has been struggling to be something other than the sleepy little hamlet it once was.

But over the past year, Leesburg has boomed.

According to some city and county officials, Leesburg is "exploding." It has become a "boom town" built by tourism and business. If you doubt that, try to get a motel room in town even on a Monday night.

"We're full almost every night all year long," said Sigwick Inn owner John Sigilitto. "There has been a definite increase in tourism in Leesburg and we're interested in cultivating it."

Sigilitto said the upturn in his business, which he has owned for nearly three years, came in 1983 when the economy generally was enjoying a healthy surge. He vigorously pursues the "business market" -- travelers from Dulles International Airport who can't get rooms at the Marriott or the Holiday Inn. One night last week, 45 rooms were being used by flight crews.

There are 130 rooms available for the overnight Leesburg visitor, including two country inns. In response to the westward push of tourism and economic development through Leesburg, town fathers have approved rezoning within the last year for the construction of three new motels, which will bring the total number of rooms available by 1986 up to 453. Market Square Station, a multiuse development under construction in town, will house, among other things, three quality restaurants to complement restaurants such as the Colonial, Green Tree and Laurel Brigade inns downtown.

Another attraction officials believe will bring in more tourists is the Washington and Old Dominion Bike Trail that begins in Arlington. It is slated for completion through Leesburg within the month.

The proximity of Dulles Airport, the recently completed Dulles Toll Road and the even more recent announcement by Pan American World Airways that it will use the airport as a hub for its flights to Europe and South and Central America beginning Saturday, will continue to spur growth throughout Loudoun, as will several huge projects, including a multimillion dollar commercial and residential Xerox development and the Center for Innovative Technology.

But some Leesburg officials, who believe that tourism is, next to agriculture, the county's biggest moneymaker, are working to preserve the town as it was 235 years ago. Ball's Bluff National Cemetery and Battlefield near Leesburg, 475 acres of hilly forest land, were recently designated a national historic landmark.

According to county tourism director Hugh Harmon and County Board Chairman Frank Raflo, the county is trying to persuade the National Park Service to acquire the battlefield. That, said Raflo, could bring in $200,000 annually.

Although the town of Leesburg and county tourism officials have never done a study on what tourism means to Leesburg in terms of revenue, Raflo estimates the county figure at $30 million annually, growing by about 10 percent every year. Last year 31,000 tourists stopped in the Visitors Center on West Loudoun Street.

Raflo, once Leesburg's mayor and several times president of the county's Chamber of Commerce, said the boards of Fauquier and Loudoun counties took a land-use planning tour in England in 1972. "The most important thing we learned was that the tourist dollar is the basis for preservation and conservation of a way of life." That concept was brought home to him, Raflo said, when the group visited a castle built in 860 A.D. "The armory and the dungeon were cold and wet, just like they were when the castle was built. But the tourist shop, right next to them, was warm and well-lighted."

A former Leesburg resident who visited last week was shocked at the changes in the town. "The crowded streets, the tourists, the new restaurants, the brick sidewalks . . . I couldn't believe it," he said.

If it has changed, what has been preserved?

The buildings mostly. A walking tour of the city will reveal to the tourist's wandering eye at least 50 buildings restored and preserved much as they were over 100 or 200 years ago. One of the oldest is the Patterson House, a Georgian-style stone building built in 1759 now filled with business offices.

Leesburg, one of only five Virginia towns to be named a National Historic District, has an architectural review board that oversees new construction to ensure it is compatible with the old and restoration efforts to ensure authenticity. Said Raflo, "We try not to be colonial. We just want to be what we had been -- a rural town with a mixture of architectural designs."

In an effort to spur tourism and thus preserve what is most appealing about Leesburg and the county, Raflo recently spearheaded a drive that saw tourism separated from the Department of Economic Development by a 5-to-3 board vote. Although county officials are seeking larger quarters for Hugh Harmon and his staff of one, no additional funds were allotted for tourism in the 1985-86 budget. About $176,000 -- $1000 more than last year -- will be spent this year, mostly on publications designed to lure the tourists from Washington and surrounding states.

"We just want to make'em come out, look at the cows, go to the toilet, spend their money and go home," Raflo said.