Al Farrington is no kind of cowboy, urban or otherwise. A 25-year-old graduate of Indiana University, Farrington has bounced around Michigan and New Jersey, lives in Fairfax and works a coat-and-tie job downtown with a big mortgage broker.

But yesterday afternoon Farrington was wading through mud and a sea of ten-gallon hats at Bull Run Regional Park in Fairfax County, drawn there by the whine of fiddles and the twang of pedal steel guitars. It was oppressively humid, and Farrington figures himself as mostly a rock-and-roll kind of guy. But somehow, like about 10,000 other people, he ended up killing the day at the 11th annual Bull Run Country Jamboree -- and smiling all the way through it.

"I've never been one to seek out country," Farrington said, a slightly self-conscious grin darting across his face. "All my friends and I listen to rock-and-roll. We have since we were kids.

"But as I've grown older, I've begun to appreciate country music. I listen to the normal stuff that's played on the radio. Mostly, I'm here for Ricky Skaggs," a guitarist and singer whose background is traditional bluegrass. "There's just something about the music you can't ignore."

The foot-stompin' crowd at Bull Run, and a growing number of people across the region, seem to agree. Washington may tout its increasing high-culture sophistication, but many of its residents are hooked on the down-home sound of country-and-western music. And yesterday, a public park was transformed into the biggest honky-tonk in town.

The festival, which featured big-name country acts such as Skaggs, Alexandria's Mary Chapin Carpenter, Garth Brooks, T. Graham Brown and Ricky Van Shelton, is sponsored by the Northern Virginia Regional Park Authority, which operates Bull Run Park. When the agency launched the event in 1979, there were so few commercial venues for live country music in the Washington area that officials felt government should get involved.

Today the region supports a number of successful country and bluegrass nightclubs, one of its top-rated radio stations plays country, and fans are as apt to be found in boardrooms as in barrooms. One of the music's biggest aficionados is an erstwhile Ivy Leaguer named George Bush.

And the Bull Run Jamboree has grown into what one park official proudly described as "the granddaddy" of country festivals in the area. Until this year the event had been held in an undeveloped corner of the 5,000-acre park, a meadow beside Bull Run. But yesterday's festival marked the opening of a new amphitheater just off Interstate 66 west of Centreville capable of seating 22,000 people.

"You're looking at a facility that will grow slowly and carefully over the next 12 or 15 years," said Darrell Winslow, executive director of the regional park authority. "The jamboree will continue to be here, but we hope to have other events as well. We hope the park and the amphitheater will increasingly be a focus for life in the area."

Winslow said "everything worked real smooth" in the arena's debut, although recent rains turned portions of the grassy spectators area and parking lot into a muddy bog. Future improvements to the amphitheater are likely to include water-resistant pedestrian paths and lights to allow events to be held at night.

Country music is likely to remain a fixture at the facility, in large part because of its proven drawing power. "It comes as a surprise to a lot of people, but the Washington area is one of the strongest country music areas in this country," said O. Joe Faires, the promoter who put together the festival for the park authority. "The number of people who attend shows is very high. And you draw everything from blue-collar workers to bank presidents."

Faires credits the music's popularity to two factors: its incorporation of other popular music forms, especially rock and blues, and its tradition of memorable lyrics.

"The music itself is about everyday life," Faires said. "It says things people can relate to and it says them in ways people can remember. It's America's music.

"And a lot of what country is wasn't country long ago. The music draws on a lot of sources. What used to be pop music in the '50s and '60s is now country music. People like Billy Joe Royal, Brenda Lee and B.J. Thomas, who used to play rock, are doing country now."

One example of country's recent musical diversity is singer T. Graham Brown, who began his career as a student at the University of Georgia singing soul music. He drifted into country, he said yesterday, after moving to country music's capital, Nashville.

"They told me to make a career {in music} I had to move to New York, Los Angeles or Nashville, and I was too scared to move anywhere but Nashville," said Brown, a Georgia native. "I've done blues, I've done rock, and it all sort of blended together in Nashville. It's country; I just don't know what country it's from."

The music's catchiness and calculated ear appeal were evident in song titles such as one performed by Garth Brooks, "We Bury the Hatchet, But Leave the Handle Sticking Out."

Brooks cites musical influences as diverse as James Taylor and George Jones and refuses to categorize his music. "What we decided to do {when writing songs} is go from the heart to the heart in a straight line," Brooks said. "Not everybody is country or rock-and-roll. But everybody has a heart."

Which is exactly why a die-hard group of country fans from Manassas spent the day at Bull Run. Cotton Lawhorn, a 24-year-old auto painter, and Mike Preston, a 23-year-old cable splicer, say they grew up on country and have listened to very little rock.

" 'Help Me Hold On' by T. Graham Brown is the story of my life," Lawhorn said. "There's a story behind every song. They say it all. And that's what country music does."

Preston, who described himself as "born to boogie," said country music for him means good times, pure and simple. "We're just hard-working men out here on the weekend having some fun and raising some hell," he said. "Ain't nothing wrong with that."