For most of her professional life, Cate Magennis thrived on being in the center of things. From her first internship in Washington in the Carter White House to her years as a real estate developer in Loudoun County, she seemed to be everywhere.

She was a regular in the social columns. Her friends were senators and governors. She served as Virginia's secretary of commerce. She helped develop the Lansdowne community in Leesburg. When she planned a millennium party, she did it big time -- at the Great Pyramid of Cheops.

Today, Cate Magennis Wyatt walks 200 yards from home to work above the village post office. She devotes herself to saving a nearby farm from development. Her proudest recent project is the treehouse her family built in the back yard.

Wyatt has lived in Old Town Alexandria, McLean and London. Through much of the 1990s, she commuted to Moscow and Kazakhstan, where she and husband Steven Wyatt ran an oil business. But after several years of life in London's Regent's Park, with her two children "in very English schools and a lot of fancy parties, well, it wasn't an epiphany, but you come back home and you realize that a lot of that doesn't matter. We decided we can live a much simpler life and still do business by cell phone and e-mail."

Cate Wyatt lives where she lives because in Waterford, a Colonial-era village of 90 houses in a piece of northern Loudoun County that sprawl has not reached, "the children can be Tom Sawyer and Huck Finn. If they cut through someone's yard and trample a tulip, they're going to be called in and have to replace it. And if they skin a knee, somebody's right there to pick them up."

Kids are everywhere on Waterford's narrow sidewalks. They're making chalk drawings in front of the house next door, where a neighbor runs an art camp. They're down the road, in Catoctin Creek, where Cate's 5-year-old was playing one day soon after the family moved back from London. He came running into the house, shouting, "Mummy, I've just caught a crawfish!"

"I was never happier than that moment, to see him with a crawfish in his muddy little hands," his mother recalls. "That was why we came back."

Since moving full time to Waterford, where she originally bought her brick-and-stone 1795 house as a weekend retreat, Wyatt has become a determined advocate for preserving the village and Loudoun's remaining rural portions against the tidal force of sprawl. She led a campaign to save a 144-acre farm at the edge of the village; a developer had sought to build 14 houses there, but Wyatt led a drive to raise nearly $4 million to buy the land for the Waterford Foundation, which will preserve it as green space.

Now Wyatt has taken charge of the Journey Through Hallowed Ground, an effort to preserve the history-drenched 175-mile corridor from Gettysburg to Monticello -- an area that includes six presidents' homes and many of the most important Civil War battlefields but is also directly in the path of development extending from Washington.

That role seems like a turnabout for a developer, but Wyatt doesn't see it that way: "You can stand outside with a picket sign, or you can be inside making decisions that respect history and balance growth with preservation."

From inside, she has found most developers to be willing to steer clear of historic lands, understanding that unless those places are preserved, the rest of the region becomes much less valuable in every way.

The town where Wyatt grew up, Wethersfield, Conn., changed drastically during her youth, as bulldozers transformed farms into "Everywhere, America," a vast suburb. But Wyatt believes that she has found a place where that will not happen. "The voters want to keep the rural communities rural; I have to believe that the will of the people will prevail."

Wyatt had to move 47 miles outside Washington to find the idyll she wanted; she is frank enough to say that if she were still commuting to the District, she would not choose to live this far away.

But "I've been lucky enough to have a choice and to be able to work from here," she says. And here she stays, in a village where no one lives in a development and doors are unlocked and kids roam around on their own.

This is the first in a series of columns to appear every month or so in which people explain why they live where they live.