The annual performance returns Thursday at the Creekside Pavilion, where organizers say audiences can expect nearly 50 songs spanning classic rock, country and other popular genres. Music begins around 5 p.m. and continues into the evening.

What many attendees don’t see is the extensive preparation that begins months before the first note is played.

Organizer Pat Hackett says planning starts each year on Oct. 1, after taking a break following the previous year’s show. Musicians submit hundreds of song suggestions, which are gradually narrowed into a final setlist by Halloween. By Thanksgiving, the songs are arranged into a carefully planned performance order, and by Christmas, individual musicians receive their assignments to begin rehearsing.

“It’s like coaching a football team,” Hackett said. “You match the songs to the strengths and talents of the musicians you have.”

Not every song makes the final show. Organizers say songs are cut if they can’t be performed at the quality audiences expect, even if they’re popular requests.

The final production features a rotating cast of performers. While a small core group returns each year, many musicians come and go depending on their schedules. Since the concert began in 2011, no two lineups have been exactly the same.

The event has become known for keeping audiences guessing. Organizers intentionally do not release the setlist ahead of time, allowing each song to be a surprise throughout the evening.

The concert has grown into one of Warren’s most anticipated annual events, drawing thousands of people to the Creekside Pavilion while neighbors enjoy the music from porches, backyards and the nearby bike trail.

The current venue has become an important part of the event’s success. Organizers credited Tom Pellegrino for building the Creekside Pavilion and providing the space for the concert, calling his commitment to the community invaluable.

Food and beverages, including alcohol, are sold exclusively through Pellegrino’s during the event, with proceeds helping support operation of the venue.

Beyond the music, organizers say the concert is about bringing the community together.

“This is the way people used to be,” Pellegrino said. “For those few hours, everybody comes together again.”

The event also serves as a showcase for Warren County’s local music scene, with members of numerous area bands performing, volunteering and supporting one another throughout the year.

“It’s a very supportive atmosphere,” Hackett said. “If we’re not playing with each other, we’re out supporting each other’s shows.”

Despite the concert’s size, no one involved is paid. Musicians travel from across the country, bringing their own equipment and volunteering their time simply for the opportunity to perform.

“As long as I can draw breath and I’m healthy enough to come back here,” Hackett said, “we’re going to keep doing this.”

While the musicians receive much of the attention during the concert, organizers emphasized that a dedicated behind-the-scenes crew keeps the production running smoothly.

Scott Taylor oversees monitor sound, allowing performers on stage to hear themselves and each other, while front-of-house engineer Bob Volpe manages the audience sound mix. Stage manager Ward Schell coordinates musicians as they rotate on and off stage throughout the evening.

The concert’s volunteer spirit extends beyond the musicians.

“Everybody does this for the love of music, the community and rock and roll,” Hackett said.

That sense of community has helped the event grow steadily over the past decade. What began in 2011 with an audience of roughly 250 to 300 people performing from a flatbed trailer on Liberty Street has evolved into one of Warren’s largest annual community gatherings.

“It’s taken on a life of its own,” Hackett said.

The event has also become a reunion destination. Organizers said many Warren Area High School graduating classes now schedule reunions during Fourth of July week so classmates can attend the concert together.

Pellegrino said the popularity of the River Monsters inspired him to expand programming at the Creekside Pavilion, creating a summer concert series featuring tribute bands and touring acts.

“Seeing all these people come together made me want to give them more reasons to come downtown,” Pellegrino said.

Despite attracting large crowds, organizers say the venue has remained family-friendly.

The event also serves as a way to encourage the next generation of local musicians.

Elementary music teacher Parker Neal again plans to bring a children’s chorus this year, joined for the first time by a youth drum line. Organizers also expect an 11-year-old musician to perform alongside the adult band.

The Allegheny River Monsters also continue to support music education through annual T-shirt sales, with every dollar of profit donated to Warren Area High School’s music boosters and marching band.

“We’re trying to get younger people involved,” Taylor said. “Someday they’re going to be the ones carrying this forward.”

For Pellegrino, however, the concerts represent something larger than music.

“If we can get families spending time together again and pass those values on to their kids, that’s what matters.”

Behind the experience is a production that has become increasingly polished over the years.

Sound equipment is positioned well before musicians arrive, allowing performers to simply plug in and complete a streamlined sound check. Organizers say every year brings small improvements that make setup more efficient while enhancing the experience for the audience.

“This is a very professional production,” Hackett said. “I’ve played on stages all over the country, and this setup is as good as any of them.”

As the July 2 concert approaches, organizers say their focus remains unchanged: presenting a free evening of music that brings together neighbors, families and visitors during one of Warren’s busiest weeks of the year.

What started more than a decade ago with a few hundred people gathered around a flatbed trailer has evolved into a signature community tradition. Yet those behind the event say its success isn’t measured by attendance or the number of songs performed.

Instead, it’s found in the conversations between old friends, the families gathered along the river, the children performing alongside veteran musicians and the thousands of people who return each year to celebrate music together.

For one evening each summer, organizers say, the Allegheny River Monsters concert is about more than rock and roll. It’s about giving the community a place to gather and a reason to keep coming back.