Glebe House has stood on a grassy knoll in Arlington County for more than 200 years, a rambling white-frame symbol of Northern Virginia's agrarian past that is today surrounded by a forest of brick colonials.

But with a subway line to the south, a booming commercial strip to the north and a developer pushing to build a town house project in its back yard, Arlington's oldest parsonage is fast becoming a symbol of a different sort. It is a house caught between the profits to be made in an expanding real estate market and a neighborhood's efforts to resist change.

"This is a single family detached neighborhood," said David K. Martin, a member of an ad hoc group that is fighting plans by developer Preston Caruthers to build 11 town houses on the landmark's two-acre lot. "We don't want to see an encroachment of the development that is creeping like athlete's foot from Ballston on the south and Lee Highway on the north."

Caruthers, a prominent local businessman who once was chairman of the Arlington School Board, professes bewilderment over the controversy, which has inflamed tempers in the quiet neighborhood just east of Glebe Road between I-66 and Lee Highway.

"This isn't a stately mansion that people would pay to see," said Caruthers, adding that it just isn't economically practical to substitute a few large homes for the town houses, as neighbors have urged. "I don't think they know what they're talking about," he said.

Local and national planning officials say the land war being waged in North Arlington these days is far from unique. In urban areas across the nation, they say, neighbors are waging battles--most of them unsuccessful--to fight the construction of attached housing in single-family neighborhoods under local "cluster" ordinances.

Such ordinances allow developers to place housing units close together while leaving other portions of their land vacant, clearing the way for the development of isolated lots that have previously gone begging because historic features and topographical problems prevented their division into rectangular parcels.

"Clustering has been around for a while, and it's growing in popularity," said Welford G. Sanders, a spokesman for the American Planning Association. "There's definitely a trend to smaller units and attached units. Many developers feel that's where the market is."

Builders argue that clustering does not increase the number of houses allowed under present zoning. Instead, the same number of units are concentrated on one section of a tract while leaving the rest as open space. Developers then reap bigger profits because attached units are cheaper to build.

"People think these single-family houses are sacred, even though they are a poor use of the land," said Caruthers, one of the builders who helped transform Arlington from dairy farms to suburbia 30 years ago. "How much better we would have been if we had clustered those houses and left the rest as parkland."

Neighbors of the Glebe House fear that clustered development could permit the National Genealogical Society, which is planning to buy the structure, to knock down the historic house and put still more development in its place. "If you've got the genealogical society there today, you've got the 7-Eleven there tomorrow," said Martin, who can now look out his living room window at the Glebe's grassy side yard.

Arlington enacted its cluster ordinance almost 10 years ago, after most of the county's rolling farmland had been built on and many of the vacant lots that remained had topographical and other problems that would otherwise have stymied the construction of single-family houses.

Since that time, county staffers say, developers have proposed more than 15 cluster projects and most have met with community opposition. County staffers recall only two cases, however, in which neighbors were successful in stalling or stopping the development.

"The question was whether you could discriminate against landowners that had these problems on their properties," said county planner Hal Glidden. "Everyone else has gotten the maximum density allowed under the zoning. It's kind of hard to treat them as second class citizens."

Under plans pending before the county planning commission, Caruthers would place his two- and three-bedroom units on the back acre of the Glebe property around an octagonal drive, designed to echo the octagonal design of a wing of the house.

The house, which was built in 1770 as a minister's rectory for Fairfax Parish during the time that George Washington was a parish vestryman, would then be leased to the genealogical society for six years. The society has agreed to acquire the property after that time, he said, and preserve it as a historic landmark.

Caruthers said he was planning to buy the house and surrounding land for $475,000 from lawyer Frank Ball, whose family has owned it since the 1920s, and to sell the units for between $175,000 and $180,000 each. The surrounding houses are valued at an average of $108,000.

"We ain't a bunch of hippies," said Martin, whose group is trying to stall approval of the plan until it can work out a compromise with Caruthers. "We're just a bunch of aging middle-class people trying to be reasonable about what's best for our neighborhood . . . .

"What if they had sold off the Ellipse near the White House and somebody said, 'I'll build town houses that are in keeping with the White House.' Well, nonsense. The land itself is significant to the White House. And we feel the same way about the Glebe."