When Kristi Rosenbaum first saw her new home four years ago, it was nothing more than a stake in the ground marking lot 36-B. Surrounding that were acres of even more construction-ready dirt.

For Rosenbaum, this was a prime selling point: She liked the idea of having space. So did others who chose to live in Sheffield, a Gaithersburg neighborhood of about 150 homes on nearly half-acre lots.

Rosenbaum, the mother of three children younger than 6, said she appreciates both her big lot and her spacious 4,000-square-foot house. In Kensington, where she and her husband, Peter, used to live, "My neighbors were either right next to me -- or my kids were right next to me," she joked.

Rosenbaum said her husband, who works in sales, was a little harder to convince at first. He grew up in Bethesda and used to consider Gaithersburg the boonies, she said.

But now, she said, he has grown fond of the neighborhood, where stray basketballs and fallen bicycles sit in front lawns.

Ali Memon, who retired from the World Bank and works as a consultant out of his home office, typically takes advantage of the airy neighborhood in the evening. That's when, he said, "I see my sunset and walk on these peaceful streets." Several of those streets have "Star Trek"-inspired names -- including Reliant Drive, Intrepid Lane and Tribble Way.

Indoors, his wife, Razia, pointed out, there's plenty of space, too: All the homes are roomy, with high ceilings.

"I couldn't stand living one house after another," said resident Debbie Milder, whose back yard faces the county's 410-acre Agricultural History Farm Park.

This buffer and other parks along Sheffield's perimeter prevent more private development, said Steve Hoffman, president of the Estates at Pope Farm homeowners association, which includes Sheffield and two other nearby neighborhoods.

"Even in Montgomery County, where parkland is very plentiful, Sheffield really has an unbelievable amount of parkland surrounding it," said Derick Berlage, chairman of the Montgomery County Planning Board.

A new 51-acre park is even in the works about a mile south of Sheffield, said Berlage: Laytonia Recreational Park, which should be done in 2011, will include four baseball fields, an in-line skate hockey rink, a playground and picnic shelters.

In the meantime, neighborhood children have Sheffield's very own playground. "It's just very family-oriented," said Jim Ladas, an investment banker. He and his wife, Wendy, have three young children.

Family is "the best part of living here," said Razia Memon, whose daughter's family and in-laws live in two houses just around the corner. If her two grandsons don't visit, she can't stay away for even a day, said Memon, who regularly baby-sits the youngest and also helps manage residential properties she and her husband own.

The Memons were not the only residents who bought Sheffield homes because of who their neighbors would be. Debbie Milder's family and Frank and Innocent Byamugisha, neighbors for five years in a nearby Gaithersburg neighborhood, moved into some of the first homes on Reliant Drive.

"And they still live on our left," Milder said. "It all happened because Frank said, 'You can't move away from us.' "

Several residents, including the Rosenbaum and Ladas families, said they appreciate a community where something like the out-of-place "purple door" isn't welcome unless authorized by the homeowners association.

The Rosenbaums recently gave their daughter, Madison, a little shed that looks like a mini-house for her sixth birthday. To get association approval, Kristi Rosenbaum had to fill out an application and get four signatures from nearby neighbors. The association approved it, as long as she agreed to put it at the farthest point of her property along the park area.

Sheffield's spacious lots don't prevent neighbors from socializing. Neither does the road dividing them: Airpark Road splits the neighborhood into two parts, known to residents as Sheffield One, developed about four years ago, and Sheffield Two, developed about two years ago.

The Reliant Ladies, who take their name from one of the neighborhood streets, are a social group of about 30 women who meet the third Monday of the month, said Rosenbaum.

The only rules: No children or husbands, and bring food only if you want to, Rosenbaum said.

Jim Ladas said dads don't feel left out.

"Guys just aren't like that," said Ladas, who is satisfied mingling with neighbors at community events.

The community association's social committee organizes community events about four times a year, said Hoffman, the association president. These include gatherings such as the October Fest today, where the association provides food and even a moon bounce for the kids.

"And, of course, there's beer," Hoffman said.

Peter and Kristi Rosenbaum, with children Grant, left, Madison and Turner, in their back yard. Jim and Wendy Ladas, with children C.J., 4, Lindsay, 6, and Sean, 1, often spend summer nights at nearby Rio Center to watch their favorite bands. The neighborhood has a playground where families meet for play dates.Ali and Razia Memon moved to Sheffield to be closer to their daughter's family.