NVLand, a development firm based in McLean, has purchased a 450-acre farm adjacent to the Leesburg Municipal Airport for about $13 million and plans to develop it into a mixture of residential and employment center uses.

Known as the Henry Stowers Farm, the tract is considered to be one of the most valuable sites in the rapidly developing Leesburg area by Loudoun County developers and brokers. The acreage is south of Rte. 7, east of Rte. 15 and adjacent to and accessible from the Rte. 15 bypass.

"Because of the location and potential development , it is one of the key pieces of ground. It commanded top dollar," said Fred Hetzel, past president of the Virginia Association of Realtors and a residential and commercial real estate broker based in Leesburg.

Local brokers estimated NVLand's price at $28,000 to $30,000 per acre, which they described as "a premium price," even in today's escalating marketplace. NVLand, which operates in Fairfax, Montgomery and Loudoun counties, declined to verify the amount paid for the farm.

David Flanagan, vice president of NVLand, said, "It is the prettiest site we have ever bought."

The acreage is immediately north of the Leesburg Airport, which is to be expanded in the near future to accommodate corporate jet service. The tract would be almost a perfect square, bounded by Rtes. 621, 654, 643 and the bypass, except that the southwest corner is occupied by the Simpson Middle School. But the farm would be bisected by the planned westward extension of the Dulles Toll Road through Loudoun County.

The rolling terrain includes only 10 acres of heavily wooded land. The remainder of it has green fields ripe for development.

The farm was annexed by Leesburg several years ago and rezoned for intense development. The master plan for the site calls for construction of a mixed-use development, including residential units and employment centers, according to the Leesburg land use plan.

Dwight Schar, chief executive officer of NV Companies, said his staff and consultants will work with Leesburg officials to better define how the area set aside for "employment" development should be utilized. Flanagan said that plans are "very early, very preliminary."

The developers said they do not know exactly how many residential units will be built, but that whatever is built will conform to the existing land use plan.

Schar said residential units would include "some rental apartments, condominiums, town houses and detached houses." Most of the housing will be built by either NVHomes or Cross Builders, both of which are part of the NV organization. Schar said some residential sites might be made available to other builders, depending on final development plans.

Hetzel said several other developers had tried to buy the Stowers farm in recent months but had been unable to complete a deal. He called the site the "key piece in the future development of Leesburg."