By Eugene L. Meyer

Who lives here: Since 1990, the county population has nearly tripled to 256,000 people, many of them young families looking for good schools and a big yard. Median household income is $98,483, the highest in the country.

The vibe: Loudoun is a county of contrasts, with its overdeveloped eastern end and its rustic western end of horse farms and quaint villages.

Homefront: Modest homes—whether new townhouses or starter single-family homes—dominate the eastern end, from Dulles Airport to the Potomac. Loudoun also has older houses of frame and stone in historic communities such as Waterford, founded in 1733 by Quakers.

Two-thirds of the county’s 93,000 homes have been built since 1990, some of them in remote areas. “We can’t even get a pizza delivered out here, and that’s the way I like it,” says Lee Fahrner, who recently moved from busy Sterling to an $865,000 home in Waterford Ridge, an area of three-acre lots outside Waterford.

What homes cost: Last year the average resale price held flat at $547,000, though homes took longer to sell—an average of 79 days versus 26 in 2005.

Llangollen Farm, a 1,100-acre horse estate with an 18th-century manor house, recently sold for a county record of $22 million.

Local favorites: Old-time country dances at Purcellville Skating Rink; Leesburg’s Tuscarora Mill, known as Tuskie’s, a former flour mill turned restaurant; and Middleburg’s Hunt and Christmas parades. Waterford Market, that town’s only store, sells lamb sausage, canned goods, and handmade items.

What’s new: Historic Morven Park, in Leesburg, hosts in May the first-ever America’s Cup of Polo, with a match between teams from the United States and the United Kingdom.

Biggest draws: Seven mostly quaint incorporated towns—including Leesburg and Middleburg—and many more villages. Rolling countryside and Blue Ridge mountain views dominate the western landscape.

Drawbacks: Growth has brought traffic, alleviated some by bypasses and highways such as the Greenway toll road. Six of the county’s ten most dangerous intersections are along heavily developed Route 7 in eastern Loudoun. Express bus service to Rosslyn, the Pentagon, and DC offers an alternative to hours at the wheel.

How it beats Howard: It’s twice the size and has more undeveloped land. Loudoun also has Dulles, AOL, and other large employers.

On the Web: Loudoun County Library links (lcpl.lib.va.us); Loudoun Times-Mirror newspaper (www.loudountimes.com); Loudoun County government (loudoun.gov).