RICHMOND — Dennis Hoskins II was looking for a place to ride.

The former bike messenger and Richmond resident had gotten his son, Zakell, into bicycling and wanted to take him to dirt tracks to practice mountain biking and BMX skills. But, the closest ones in Napa, Novato and Pleasanton were all hour-long drives. So, he and Zakell’s mom, Jasmin Malabed, decided to build a track of their own.

That started a nearly four-year journey culminating this week in the opening of Dirt World, the Bay Area’s only urban BMX park accessible by BART. Nestled between 20th and 21st streets along the Richmond Greenway Trail, the 2.1-acre park features jumps for BMX riders of varying experience levels, a half-pipe, a mountain biking skills and race course, and a pump track — a circuit of banked turns and bumps meant to be ridden using the momentum of the bike against the trail — along with an outdoor seating area and gathering spaces.

Eventually, it’ll include a classroom space and one day become the official training ground for a BMX racing team out of Richmond, serving as a complement to the city’s high school mountain biking team, which this year completed its first season, Hoskins said.

“When you’re here, you kind of forget where you are,” Hoskins said, looking out over the brown-field site that’s now been repopulated with non-toxic dirt and shaped into a hilly expanse. Mount Tamalpais, the birthplace of modern mountain biking, rises in the distance behind it. “We had to completely change the face of what was going on here.”

It wasn’t easy.

Hoskins and Malabed first got started in 2015, helping lead the construction of a pump track at Richmond’s John F. Kennedy Park. The small skills park was great for their sons, now aged 9 and 7, and teenage daughter, to learn the basics. And, the story might have ended there, if a city worker hadn’t mentioned the lot to them one day, Hoskins said. He knew exactly the one.

Choked with weeds and littered with trash, the lot had been a magnet for illegal dumping and was home to people sleeping outside. The post office building abutting the greenway was tagged with graffiti. People would throw rocks at the windows of homes adjacent to the former railroad tracks, Hoskins said. He’d pass by it on his way home, sometimes stopping with his sons to sit in the field and imagine what it could be, he said.

Building off the success of the pump track, Hoskins and Malabed began to think bigger. They found support from Rich City Rides, a nonprofit bicycle organization and repair shop; Action Sports Construction, which specializes in track-building and helped translate the community-led vision into a cohesive park; and landscape architect Jeanine Strickland. The city agreed to let their group adopt the lot, so long as it didn’t need to maintain it. Volunteers helped pull weeds and break up the hard-packed clay. Construction companies donated some 4,000 yards of dirt.

But, they still needed to raise funds to rent construction equipment, plant trees and build the gathering spaces. They held three different GoFundMe campaigns, which together generated about $18,000, said AC Thompson, one of the core volunteers. They convinced Title Nine, a sportswear company with a distribution center in Richmond, to help sponsor the project.

“As the process went along and we could actually show people were building something and we weren’t just a bunch of crazy people from Richmond, then it became much easier to fundraise,” he said.

The bulk of construction got underway in March, and on Sunday, Hoskins, Malabed and others were busy raking rocks from the trails and spraying water on the dirt. They still need to use a machine to compact the soil and harden it, with the goal of having only minimal continued maintenance, which will be led by volunteers.

“I don’t always want to be here,” Hoskins said. “I want to create a nice team of people who have love for the bikes and just pass it on.”

Cameren Simons, 14, is planning on helping lead that effort. He used to ride around the city on his bike with his dad, he said, until Hoskins and Malabed finished the pump track at Kennedy Park. The first time riding there changed everything, he said.

“I just loved it ever since,” he said. Now he’s hooked, even though his friends would prefer to pop wheelies and ride around in the streets. Hoskins is hoping the park will provide a better direction for young people to get out of the streets, he said. Simons is just excited to ride.

“Everybody is waiting for this park to open,” he said, “including me.”

That’s exactly what the park is for, Malabed said, not just her kids, but everyone in Richmond.

“There are a lot of kids with talent who don’t have anywhere to practice,” she said, “who don’t even know they’re good, yet.”