Florida Georgia Line performs as part of the St. Leonard Volunteer Fire Department concert series. (Kyle Gustafson/FTWP)

Talk to enough people in St. Leonard and you’ll hear the story — more than a few times — about the day country music superstar Luke Bryan was spotted at World Gym, just down the road at a strip mall in Prince Frederick. The singer worked out for an hour and then posed for photos with fans.

“My friend has the picture on her phone,” Terry Trefry says with a trace of regret. She didn’t hit the gym that day.

Unusual as it seems, St. Leonard (population 751) becomes a major hub of the country music scene for a few days each year. The tiny Calvert County community’s volunteer fire department has hosted a summer concert series for nearly a decade, pulling in big-name acts to raise money for the organization. Bryan — who just spent two weeks at the top of the Billboard albums chart — appeared last year; he was preceded by fellow chart-toppers Reba McEntire, Blake Shelton, Sugarland and Alan Jackson.

The spectacle keeps growing. Last weekend, Gary Allan and Florida Georgia Line performed in front of a sold-out crowd, with nearly 6,300 people packed into the sprawling field next to the firehouse on Calvert Beach Road; this Sunday, rising star Brantley Gilbert takes the stage for the final show of the season.

In the early days of what is now an annual tradition, some had doubts it could work. At first, no one knew if such an off-the-radar event could recruit popular performers. People said, “Those acts are too big for you,” remembers Roberta Baker, co-chair of the concert committee.

“Well,” she said, “we got them.”

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A country music concert in St. Leonard may feature the same acts as the Washington area’s largest venues — in fact, Allan, Gilbert and Florida Georgia Line all will play at the nearly 20,000-capacity Merriweather Post Pavilion later this month. The main difference is that the rural community actually resembles the small towns that country artists often sing about.

On concert days, the town descends on the fire department. The event is almost entirely volunteer-run. Everybody knows one another. Cars and trucks line up bumper to bumper on the road next to the field; some park their RVs in the adjacent lot, where they can tailgate and then spend the night.

Inside the fire hall, a small army of volunteers devours a meal before work begins. During each show, the department’s regularly scheduled volunteer firefighters and EMTs (still on call for fires and emergencies) ensure the event runs smoothly. They bring their kids, who bring their friends, who bring their neighbors to help. The Calvert County Sheriff’s Office pitches in, too, serving as security.

Familial lines run deep at the fire department. Bill Lankford, the other concert committee co-chair, has volunteered at the station for more than 30 years; his wife, Jen, is the fire chief.

“This department is very much like a family,” Jen said, adding that the family-friendly aspect of the concerts influences the planning process. There’s not a lot to do in Southern Maryland in the summer, and concerts are an ideal activity for restless kids on vacation.

On the concert field, filled with people from every age bracket, local vendors sell all kinds of food, and the aroma of barbecue wafts through the air. In the VIP area, a small firetruck named “Foamy” dispenses beer via tap handles built into its side. A dessert tent offers cookies for a dollar, with all proceeds going to charity. Once, a volunteer claims, someone yelled over the fence across the road, asking if they could buy some homemade fudge.

After so many years, the concerts are logistically a well-oiled machine, though things can get hectic with a sold-out crowd. This past Saturday, a sweltering August day until the sun went down, Baker was so busy that she didn’t get to personally present the traditional Calvert County-themed gift baskets to the performers. The baskets include Maryland wine, stuffed crab, kettle corn and monogrammed golf balls.

“It was the first time in eight years I didn’t meet the artists,” Baker said wistfully. But she saw that the performers all signed an official fireman’s helmet, the one that boasts signatures from every star who has played in St. Leonard. Then, the helmet goes back to where it belongs, safely locked in the fire chief’s office.

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No one can recall exactly who came up with the idea for the concert series. “Concerts were a good way to raise funds,” Baker explained. At the time, she said, the usual methods — bake sales, raffles, community dinners, boot drives — weren’t doing the trick. While concerts required much more work, it seemed like it could pay off in a big way. (The Calvert Marine Museum, in nearby Solomons, had lots of luck bringing in popular singers.)

The board of directors voted to purchase the field next to the firehouse. In 2005, they built the stage, now known as the Bayside Toyota Pavilion. In July of that year, the Charlie Daniels Band kicked off the inaugural concert.

Several hundred people showed up. It was deemed a success, and things grew from there. At first it proved a challenge to bring in buzzworthy performers, but organizers did better after employing a booking agent. Word spread in the music community that St. Leonard’s Volunteer Fire Department was a solid, well-organized place to play. That kind of reputation goes a long way in bringing in artists, no matter how big the name. A month after Charlie Daniels’s show, Lonestar played. Prominent country acts followed (Jo Dee Messina, Montgomery Gentry), along with some from outside the Nashville realm, like Lynyrd Skynyrd and Hootie and the Blowfish.

Organizers declined to disclose how much money the concerts make for the fire department, a registered nonprofit group. The only people who get paid are the artists and the sound and tech crews. Ticket prices are $35 to $55 — not inexpensive, but sometimes significantly lower than comparable shows at larger venues.

In terms of whether the concerts bring in more dollars than it costs to put them on, Baker said that some do and some don’t. But generally, the ones that turn a profit make up for the ones that do not.

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St. Leonard sits near the Chesapeake shore, about 50 miles from Washington and 70 miles from Baltimore. So, besides the paycheck, what’s in it for a popular singer or group to play a fire department fundraiser in Southern Maryland?

“Maybe it’s because Charlie Daniels said so,” jokes John Howanstein, a pastor from Calvert County who has volunteered his time taking tickets at the gate.

Or, Howanstein theorizes, just like Iowa is a necessary stop before the big stage for presidential aspirants, the St. Leonard Volunteer Fire Department is a similar experience for musicians. Also, that irresistible Americana experience — supporting local heroes at the fire department and giving back to the community — is great PR.

Exhibit A: The much-shared anecdote about the day Eric Church performed, and the volunteer firefighters had to respond to a call while eating before the show. Food went flying as everyone scrambled to get to the emergency. Church was so impressed by the scene, people said, that he left behind free concert T-shirts for every volunteer. (The shirts had graphics of marijuana leaves on them, so you might not see the firefighters wearing them too often.)

Regardless of why the stars come, it’s a thrill for diehard fans to sit in the front row and see artists who usually perform in much larger arenas. St. Leonard resident Terry Trefry — the one who would later miss catching Luke Bryan at the gym — was thrilled when she scored first-row center seats for his concert. She and a friend slept overnight outside the box office and were first in line when it opened at 9 a.m.

She hopes the concert series never stops. “It’s affordable, it’s in my backyard,” Trefry said. “Why would I need to go anywhere else?”

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The best part of a concert venue like St. Leonard is that it can be even more fun if things go awry.

It’s the first show of the year, in June, and the audience is around 1,200. That’s an unusually small number, but it’s Father’s Day and forecasters are predicting rain.

Sure enough, after a bubbly, upbeat set from former “American Idol” runner-up Lauren Alaina, the sky turns gray. Word comes from the organizers: Headliner Joe Nichols is postponed until an impending thunderstorm passes.

Groaning, some make a beeline for their cars, but there’s an advantage to the small size of the crowd — there’s room for everyone to wait out the storm in the firehouse. An excited murmur spreads as people crowd into the two huge garages, slumping on cement floors and trying to get cellphone reception. Conversation buzzes as thunder crashes outside; the kettle corn vendor senses an opportunity and sets up shop, offering snacks for $4. A basketball game is on TV.

About 90 minutes after Nichols is scheduled to perform, the worst of the rain seems to be over, and it’s safe to go back to the seats. Only moments later, a torrential downpour starts again. Still, several hundred determined concert­goers remain, and music suddenly blasts from the speakers, setting off a soaking-wet dance bash. Lights from the Sno-Tastic snow cone booth blink in the background of the pitch-black open field.

Finally, Nichols appears on stage. “Thank you very much for hanging around and making this a party,” he says. He tests out some new material on the crowd, because at this point, why not? Nichols warns the audience in advance: “I’m going to play you something ridiculous.”

In between songs, the host of the concert encourages the crowd to be even louder.

“We may be small in numbers,” the emcee announces. “But I think in Southern Maryland, we make an impact.”