At the southern edge of Fairfax, near where the Occoquan meets the Potomac, live the people beyond the malls.

Their home is Lorton, a quiet, country place without buses, shopping centers, doctors or even a Pizza Hut. There's an I-95 exit that points to Lorton, but no sign once you arrive. You're never quite sure if you're there.

"Nowhere Land," a county planner calls the area.

Bucolic, beautiful Nowhere Land, Fairfax's final frontier. Residents say they love Lorton, wouldn't live anywhere else. But like life on an island paradise, residence in Lorton has inspired a rural rock fever in many. As their neighbors in the new suburban frontiers to the north complain of encroaching urbanization, of neon signs and shopping centers and an army of social servants crowding them, some people in Lorton are crying for just those things.

They want the country. But they would like the amenities of the city, too. Without the traffic, that is.

"People in Lorton," says the Rev. Albert N. Jones, pastor of the 207-year-old Pohick church, "are a little schizophrenic about where they live."

Lorton does not really exist. It is only a post office, zip code No. 22079. The people share their land with a 3,500-acre prison, three dumps, a limestone quarry, a railroad yard and a sewage treatment plant. A few years ago, a group of residents in exclusive Hallowing Point Estates even tried to get the U.S. Postal Service to call Lorton something else. So great is the stigma.

"When you say Lorton," says Burnham Dodge, who retired to his $250,000 Potomac river front home 12 years ago from the Army Corps of Engineers, "the real estate agents have a fit. They call it Alexandria South."

But the 5,000 people who live on Lorton's 17,000 lush acres do have space -- more than three acres for every man, woman and child. It is a haven 30 minutes from a city where people live stacked, one on top of the other, in apartment buildings.

In Lorton they have the damp, fragrant smells of foot-long squash and softball-sized onions in dark country stores where pigs feet soak in glass jars behind the counter. A family of Southern Bald Eagles makes its home in the thousands of acres of protected wilderness, and riverside mansions with private docks are hunkered down the road from weather-worn houses with outdoor privies in the back and rusting clunkers out front.

George Washington worshiped in the Pohick church, and Gunston Hall, the Georgian mansion built by founding father George Mason, lies at the end of a long, magnolia-lined drive.

But even without shopping centers and gas-and-go stations, Lorton still feels the effects of urban growth to the north. Residents there say they feel like a colony: Fairfax County dumps its trash in their territory, the District harbors its criminals there. Minerals are taken from their land, county taxes from their pockets. But still Lorton has no bus service, and people must drive miles to Alexandria for social services.

That, well . . . that's the schizophrenia again.

Witness Pat Rasmussen, 38-year-old mother of five and wife of a pumpman at a Fairfax City tank farm. She works at the Hitching Post Country Store. The Rasmussens moved to Lorton 11 years ago from Lynhaven in Alexandria. "To get away from the city, the loudness and the crime; to find open spaces for the kids to grow in," Pat says. "It's so peaceful and lovely, like an old-fashioned country town."

But a second later, Pat Rasmussen says it's often a bother living in Lorton. She doesn't drive, and the nearest bus is in Fort Belvoir. Her doctor is in Alexandria. She has to go to Woodbridge to buy clothes. Her teen-agers have to ride the school bus 45 minutes to get to Hayfield High.

"It would be nice if they would build more town houses and apartments," she says. "More people would come in and somebody would think it would be profitable to build a shopping center."

Technically, Lorton doesn't exist. "There is no specific Lorton area," says county planner Jay Linard. "It just happened to be there." Lorton has no mayor, no town council. Its area is divided among three of the eight county supervisor districts: Mount Vernon, Lee and Springfield. But so sparse is the population that the area has little political clout.

Lorton is actually a collection of subdivisions, farms and parklands southeast of Rte. 1 on a boot-shaped peninsula bordered by Pohick Bay, Belmont Bay and the Potomac River. About 7,000 of its 17,000 acres are undeveloped. About 9,000 acres contain parklands like the Mason Neck National Wildlife Refuge and Pohick Bay Regional Park or the District's Lorton Reformatory.

The other 1,000 acres are left for people and what little commercial development there is. If there is a center of Lorton, it is Williamsburg Square, where a one-story brick building holds a new, store-front library (opened in July 1980 after years of citizen agitation, it replaced a bookmobile), a submarine shop, a High's store, a cleaners and a barber.

In the last five years, several hundred town houses have gone up in the Rte. 1 area near Lorton Road. Many residents, like Rasmussen and Christine Herbstreith, who travels six miles from her home in Mason Neck to the nearest 7-Eleven, would like to see more.

Herbstreith is the director of the Lorton Community Action Center, a six-year-old citizens group headquartered in a tiny, pre-fab structure with beige aluminum siding on the corner of the Gunston Elementary School grounds. The LCAC people built their headquarters, which doubles as a thrift shop, with part of a $14,000 block grant from the county three years ago. From the center, Herbstreith and her people act as a volunteer social service referral group.

"Because the nearest county social services center is 15 miles away in Alexandria," Herbstreith says, "most people who need help don't know about what they can receive. The closest day care is in Annandale. Fairfax County General Hospital is 18 miles away. Anything you need here is at least a 30-mile drive round-trip. The county treats us pretty much like we don't exist, don't have needs."

It is Herbstreith's dream to build a "supermarket of human services" near Williamsburg Square, a building that would house social workers and welfare officials, the library, a day care center and a police substation. The closest is now about 10 minutes up I-95 in West Springfield.

They have picked out 8.6 acres and have received a $94,000 block grant for a down payment on the $300,000 chunk of land. Negotiations with the private owner of the land are continuing, but even if the sale goes through, Herbstreith says, much more money will be needed.

"Our supervisors tell us yes when we ask them for something, but they always end up looking at the money problems and then they tell us, 'Yes, you can have pie in the sky, if you're willing to pay higher taxes.' But we already pay taxes. We deserve something."

Their supervisors agree. In theory. "It's hard to set up a transit system for only a handful of people," says Marie Traveski of the Springfield District. "The cost of bringing services to such a small and scattered number of people is prohibitive."

The words have a similar ring when they talk of the hoped-for shopping center. The Rte. 1 corridor is zoned for such development, but developers, county planners and supervisors say one is unlikely.

"The density of the area is too low to support that type of development," says supervisor Joe Alexander of Lee District. "There aren't the sewer hook-ups necessary and the county has no plans to put them in."

"There is too much competition from the north with the Rte. 1 corridor, and from the shopping areas in Woodbridge, Burke and Springfield," says county planner John Larsen. "A shopping area wouldn't be viable."

Even officials of the Gene B. Glick Management Corporation, Indianapolis-based builders of the area's only apartment complex, agree. There are about 300 units at their garden-apartment complex, The Woods of Fairfax, and 300 more are planned. But, one Glick spokesman says, "We're not looking at magnificent growth in the area . . . We expect a return on our investment in maybe 30 years."

"We're appealing to the people who don't want to live in the city or even the suburbs," said Fern Wittig, sales manager of the 106-unit Pohick Square town house complex across Lorton Road from the apartments. "They can buy three bedrooms here for $65,000. There's no intention for anything more in the way of development to be here."

Some residents of Lorton, particularly the newcomers, believe that will do just fine.

David Pitkins moved to Pohick Square with his wife and son in May. A student at the Capitol Seminary in Lanham, he commutes 70 miles a day and doesn't mind a bit. He used to live in Riverdale. "We were constantly harassed by fire trucks, police sirens and noise," he says.

A battery was stolen from his car, the gas siphoned out, and a rock was thrown through his window in Riverdale. Then someone broke in and stole his silver dollars. So the Pitkins moved -- "out here where it's like another country," David said.

"Not having any of those conveniences is a damn good reason for a lot of us to live here," says Dodge, the retired engineer. But then Dodge frowns. His wife, Virginia, doesn't drive, and when he was hospitalized for a week at Fairfax County General last year, she spent $500 on taxi fares back and forth.

"It would be nice," Dodge says on second thought, "if they had a bus running out here."