At the southern tip of Arlington County, King Street and Quaker Lane rim the neighborhood of Fairlington Villages like the edges of a slice of pie. Shirley Highway chops the slice in half.

Within these margins, concrete reminders of urban Arlington, lie 300 sloping acres of brick town houses, their trim porches and lawns wrapped around circular courtyards. In the quiet of late afternoon, cyclists whiz through Fairlington's streets and young parents push their toddlers on swings. Residents joke that there are more joggers than walkers.

Amid the urban jumble, Fairlington seems to have been plucked from another time and place.

In a sense, it was.

The 3,500 apartments and town houses that make up Fairlington were built in the early 1940s by the federal Defense Homes Corp. for government workers who flooded wartime Washington. (The community is located two miles south of the Pentagon.)

Thirty years later, private developers preserved the brick colonial-style shells and revamped their interiors, converting the area to a giant condominium complex that residents say they value for its "village" atmosphere.

Cheryl and Ali Sahin were living in Southwest Washington in 1976 when they went for a drive one day and ended up in Fairlington.

"We discovered it, and lo and behold, this is where we ended up," Cheryl Sahin said recently, sitting in the living room of a town house decorated in shades of beige and peach. "It's so quiet, yet close to everything. And I like the trees . . . we had lived in the District for so long, I wondered if I would really be happy, but I haven't regretted it for a minute."

Mikell Zinn, a real estate agent at Fairlington Properties Inc., said the two-bedroom town houses, priced between $110,000 and $117,000, sell the fastest. All the apartments at Fairlington are individually owned, although some, in turn, are rented. A one-bedroom apartment rents for $550 to $575 a month.

In a county with a diverse population and housing stock that includes large detached homes, two-story garden apartments and high-rise clusters, Fairlington remains oddly homogeneous.

A walk through the neighborhood reveals block after curving block of trim town houses with pitched roofs and black shutters. Andy Effron, a lawyer in the general counsel's office in the Department of Defense, said the layout reminds him of a college campus, and the neighborhood is so self-contained that some residents describe leaving as moving to "the outside."

Still, Effron and his wife Barbara, residents of Fairlington since 1978, said living there means sacrificing some aspects of the classic homeowner's dream. "The things people think about -- if your dream is four bedrooms, a family room, a library, a screened-in porch -- we don't have it here," Andy Effron said.

"What's kept us here is a sense of community," said Barbara Effron, who works as a children's librarian in Alexandria. "Our friends become our support as a family would.

"You will see people walking around Fairlington all times of day," she said. "People do know their neighbors. My children do, too. My seven-year-old would know where to get help, who our neighbors are.

"Sometimes it reminds me a little bit of my childhood. Our daughter can go outside and, without crossing a street, find several playmates," she said.

Although a restriction against black tenants was lifted in the 1950s after picketing by Congress of Racial Equality members, Fairlington's population of about 6,000 remains mostly white. According to the 1980 census, 67 percent of Fairlington residents had a college degree or more education, 66 percent held managerial or professional positions and 79 percent of the households had incomes of $25,000 or more a year. At the time, 43 percent of Arlington households as a whole had incomes that high.

"It is very homogeneous . . . but some people go there for that," said Joe Vasapoli, president of the Fairlington Citizens' Association.

Nonetheless, residents note that there are elements of diversity in Fairlington -- in the blend of single people, families with young children and elderly persons, and in the variety of reasons why they choose to live there.

Vasapoli, 34, who moved from Dupont Circle two years ago, was weary of struggling to park his car.

"I was getting a little bit tired of the hassles involved with living downtown. I wanted a little more space -- I like having a little yard, a little patio where I can cook out."

Dottie Arehart, 40, a divorced mother of two teen-age children, bought her three-bedroom Fairlington town house eight years ago. "It's an ideal community for a divorced woman with two children," she said. "You don't feel like an oddball. I didn't feel I fit in in married suburbia."

Many residents said they enjoy the sense of community, a cohesion fostered by town-house clusters that encourage residents to meet their neighbors.

The results of this closeness are visible in Fairlington's monthly newsletter, crammed with announcements about baby-sitting co-ops, an annual four-mile run, the Fairlington Creative Playschool, meetings of Fairlington Friends of the Environment and the Fairlington Citizens' Association.

Such activism is a longtime Fairlington tradition. A 10th-anniversary pamphlet written in 1953 bragged about the annual Cub Scout baseball game, the piano classes, bridge tournaments and the Fairlington Players theater group, as well as the 249 "first families" still living there.

The complex, sold by Defense Homes Corp. to private developers in 1947, fell into decline in the late 1950s and through the 1960s. The average income of residents dropped; turnover increased and tenants began to fear crime. When the CBI Fairmac Corp. announced its plans for a large-scale condominium conversion, many residents jumped at the chance to buy their homes; 73 percent of the units in Fairlington South were purchased by existing tenants.

By 1977, the $100 million condominium conversion was complete. Those years brought a different brand of activism -- Fairlington Friends of the Environment flourished and the first issue of the Fairlington newsletter, in February 1976, mentioned a yard sale in which $200 was raised to save endangered whales.

Last spring, nearly 1,000 Fairlington residents gathered for a four-day construction marathon to build a playground at Abingdon Elementary, the neighborhood school. "You could live here and never participate in any community activities, but you will be asked to," Andy Effron said.

Fairlington residents said they strongly identify with Arlington County, although a jagged border brings many of them geographically closer to Alexandria. A 1984 proposal by Alexandria City Councilman Carlyle Ring for a land swap that would give the city a portion of Fairlington south of Shirley Highway was rejected by Arlington County Board members and citizens.

Arlington County Board member John Milliken said, "I got a barrage of calls and letters saying, 'No, we like Arlington. We don't want a land swap.' The community connections there are very strong."

Today, there are changes both inside and outside Fairlington. A part of the aging Shirlington shopping center is set to reopen in October after a $30 million transformation by the Oliver T. Carr Co. into The Village at Shirlington, a complex of retail and office space and pedestrian plazas.

Inside Fairlington, there seem to be more toddlers filling the playgrounds and more tricycles parked on the lawns than there were a decade ago.

"It's a community in transition in that a lot of people who moved into Fairlington when it was turned into a condominium are at the stage of their lives when they are deciding to start families," said Ed Hilz, an 11-year Fairlington resident.

What remains is a close-knit community that pleases many residents because it reminds them of their childhoods in smaller towns, of quiet, predictable neighborhoods where everyone knew everyone.

"A lot of times, it's just nice to chat across the fence," said Sahin. "Or our neighbors come over and have coffee with us. . . . I'm from the Midwest -- people are very close there -- and I find this very nice."