Frank Maresca was 12th in line the first day houses went on sale. He and his wife, Carol, knew before they even heard the sales pitch that western Prince William County would be their new home.

"When we were standing there waiting for the doors to open, we began chatting with the people in line," said Frank Maresca. "Right from there we knew we were going to like the place."

Empty nesters entering their sixties, the Marescas were looking for far more than real estate. For about $300,000, they wanted to live in a community of like-minded folks--older but still active, many with children living in the area. The Marescas had lived in Fairfax County for 18 years, but the population there was so transient, they hardly knew the people living next door.

Now, part of the first crop of homeowners in what will be the massive, age-restricted community near Haymarket called Heritage Hunt, the Marescas say they at last have what they wanted--real neighbors.

"It's hard to go take a walk because people want to stop and talk," said Frank Maresca, 61.

As developers try to meet the demand of aging baby boomers, they are choosing to build farther away from urban centers, where land is cheaper.

In Prince William, several new or recently zoned upscale developments are luring those 55 and older. They include Heritage Hunt; a 250-house section of Dominion Golf and Country Club, also near Haymarket, that will be age-restricted; and Four Seasons of Historic Virginia, a 1,500-house development in the Dumfries District for those 55 and older that the Board of County Supervisors unanimously approved Tuesday.

To capture the hearts and wallets of couples such as the Marescas, developers are capitalizing on high-end appeal. Heritage Hunt and Dominion are both gated golf communities. Four Seasons won't have a golf course but will have a clubhouse with a pool and health club, along with bike trails and classes in ceramics and computers, among others.

"You're selling a lifestyle," said Chaman Puri, vice president of PC Homes, which is building Four Seasons.

The developers also have the right sales pitch for the county supervisors. Compared with the rest of Northern Virginia, Prince William is overwhelmingly young. The median age of its population is 29.

Prince William's schools and tax base are strained by the disproportionate number of young families who live in the plethora of affordable town homes built over the last few decades. Attracting older, wealthier couples to the county is desirable, because they offer considerable buying power without the burden of children. It's an ideal population subset for the county.

A development the size of Heritage Hunt, for example, will save the county as much as $5 million to $6 million a year compared with what a typical restricted community that size would cost, said county Planning Director Rick Lawson.

"We won't be infringing on the school division," Supervisor Maureen S. Caddigan (D-Dumfries) said of Four Seasons, which she views as a substantial victory for her district. Ten years ago, the same property was zoned for 3,000 town houses and 500 apartments, which for Dumfries would have meant more of the same.

Four Seasons "is what my district has been looking for," she said.

The appeal of Prince William's tonier age-restricted developments means that people are continuing a trek outward from the District--not only from the city to the suburbs but also from the inner suburbs to the outer ones. Many seniors attracted to Prince William already live in Northern Virginia and don't want to leave. But they want a community custom-tailored to them, with luxury homes, amenities and less traffic.

At Heritage Hunt, where houses cost $150,000 to $300,000, about 60 percent of new homeowners hail from Fairfax and 15 percent from the more crowded eastern Prince William, said Jerrold Berman, regional vice president for the builder, US Home Corp.

The area has "the benefit of being really only 20 miles from the Beltway but the advantage of being outside of the highly congested areas," Berman said. And sales at Heritage Hunt, with about 200 houses already sold and an additional 2,000 yet to be built, already have exceeded the developer's expectations.

"Our initial thought was until the golf course was finished, sales would be just moderate," Berman said. "We're nine months away from having the golf course playable, and the sales have reached a level that we would have expected with all that complete."

And for some, the attraction of Prince William is purely personal: Their children live here.

There are many "parents of younger couples who live here, who want to move here in retirement years to be close to their children," said County Board of Supervisors Chairman Kathleen K. Seefeldt (D). And the converse is true, too. Children want to be near their parents.

"We hear every year from more people who are doing their level best to be the caregivers for frail parents," Seefeldt said.

The county's 65-and-older population grew from 3 percent in 1990 to 3.2 percent in 1997. For a fast-growing county, that's a significant increase, Lawson said. And it's an indicator of a more balanced population, age-wise, that will make Prince William more like surrounding jurisdictions.

In comparison, the percentage of Fairfax's population 65 and older is 6.5 percent--more than double that of Prince William's. For Northern Virginia, the average is 12.6 percent, and nationally, 6.9 percent.

Gated luxury communities are not the only option for seniors looking for housing. There also are many more affordable houses, particularly in eastern Prince William. That's a necessity for a county with one of the highest poverty rates among seniors in Northern Virginia, said Toni Clemons-Porter, of the Prince William Area Agency on Aging.

And as the population changes, however gradually, the county must adapt its services to serve older people. On an annual survey released last week, county residents rated elderly services as their fifth-highest priority.

Ten years ago, Seefeldt said, there was no such thing as adult day care in the county. Today, there are two facilities, one at each end of the county.

This spring, the county police department offered its first senior citizens police academy, a six-week course that catered largely to older people living in the eastern end. Sixteen seniors were in the course, with many more expected this fall, said Officer Marty Leake.

For Frank and Carol Maresca, Prince William was the right move--in part because their children live nearby, in Clifton, Reston and Chantilly. The Haymarket area is still largely rural, so they shop in Warrenton and Manassas. But they know the area around them is growing, more retail is coming, and they feel they have seized a wonderful opportunity.

When "I run into people my age," said Frank Maresca, "I tell them about the place."