One afternoon last December, Carl Fischer donned a Santa Claus suit, hopped on a dog sled pulled by a team of Siberian huskies and rode into the center of downtown Purcellville. One by one, dozens of children climbed on his lap as a photographer snapped their pictures.

It was Purcellville's first "Christmas on 21st Street," an event Fischer hopes will become an annual tradition in the town where he works as a real estate agent.

"That was the greatest afternoon as I can recall," Fischer said. "You watched the children's faces light up; their parents were beaming behind them."

Purcellville felt like a community that day, he said. Hundreds of neighbors came out and everyone sang "Oh Come, All Ye Faithful" during the lighting of the town Christmas tree.

In Purcellville, which has the distinction of being the fastest-growing incorporated town in the nation's fastest-growing county, residents and officials are turning to events such as "Christmas on 21st Street" as one way to help preserve the small-town feel that has come to define life in western Loudoun.

On July 17, Purcellville will host its first "Arts in the Alley," a one-day festival designed to display the work of local and national artists and musicians as well as Loudoun students. And each Thursday afternoon this summer and fall, locally grown produce as well as wine and breads are being sold at an outdoor farmers market in the center of town.

Robert Lauten, president of the Purcellville Business Association, said the events help Loudoun's second largest town (after Leesburg) maintain its personality. "I think Leesburg and Middleburg do a great job marketing themselves, and Purcellville needs that to make the town vibrant," Lauten said. "Otherwise it's just a location for more houses. I want the town to have identity and culture . . . all that fun town stuff."

When new county figures released last month showed that Purcellville was the fastest growing of Loudoun's seven incorporated towns between 2000 and 2003 -- jumping from 3,584 residents to 4,787 -- it came as no surprise to the people who live there. And that number doesn't include residents in new developments that have sprouted up just outside the town limits.

Last summer, a second traffic light was added downtown and a Giant grocery store opened its doors. A new independent bookstore and a coffee shop popped up last year, too. And just a few months ago, Magnolias at the Mill, a restaurant run by the owners of Tuscarora Mill in Leesburg, opened in a renovated seed and feed mill.

According to recent U.S. Census and town figures, Purcellville has about 1,810 homes, up 40 percent since 2000.

Sandy Tremel, 47, who moved to town in April 2003 from Arlington County, said she's noticed the growth in the short time she's lived here with her husband and their two young daughters. "You see it in the traffic on Route 7," she said, and in the orange mesh fencing marking open lots that will soon hold homes.

Tremel said her family came to Purcellville because she decided to leave her job as a court reporter and stay home with her children. The town offered "big houses, big yards and good schools," she said, and "everybody knows everybody."

The intense growth means that local officials must spend much of their time in debates about traffic congestion, taxes, housing densities and water lines. But Town Council members say they also focus on finding ways to maintain the atmosphere and sense of community that draw people like the Tremels.

Council member Bob W. Lazaro Jr. said the town is considering a proposal that would require a special permit to open a store larger than 10,000 square feet. The proposal is headed to the Planning Commission in mid-July and should reach the council later in the summer.

The town also recently distributed free pots filled with colorful flowers to merchants who agreed to tend and water them. "It made people feel good," Lazaro said. "You have to take pride in your hometown."

Fischer, who runs All the Best Real Estate, said he thinks the town will keep growing but can stay small at heart. The next step, he said, is identifying local treasures, perhaps places with impressive views or historic structures, and working to make sure they are preserved for future generations.

"There is a real desire both in the longtime residents as well as the come-heres [newcomers] to help preserve that sense of place," Fischer said. "How do you honor and respect the past that is so important to the people who come here while at the same time making room for the goods and services that people need? There's a way to do it."

Georgia O'Neal, above, of Tree and Leaf in Waterford arranges flowers. Pat Peters, below left, of Hamilton buys fingerling potatoes from Emily Snyder at the Purcellville farmers market.