The Esplanade Association, the nonprofit that stewards the Esplanade along the Charles River, is celebrating its 25th anniversary this month.

“We are proud of our first 25 years of care for this historic urban greenspace,” the association wrote in its anniversary newsletter. “We were founded to make life better on the Esplanade for all, and that mission still rings true today.”

The idea for an association first blossomed in the 1970s with a group of Back Bay and Beacon Hill residents. During this time, a number of advocacy groups had formed for city owned parks like the Public Garden. But because the Esplanade is state owned land, none of those groups could care for it. After many years of informal organizing, the association formally began in 2001.

“You could think of our work as amplifying the care of the park beyond what our friends in the state can do,” Jen Mergel, the association’s executive director, said.

Nicole LaChapelle, the commissioner of the state’s Department of Conservation and Recreation, said that the association had been a “tireless partner” in shaping the park to be “vibrant, welcome, and accessible.”

The state is responsible for basic logistical care, like taking out the trash or turning on the water in the springtime. The association handles the details like planting trees, repairing benches, hosting free fitness classes. In 2017, for example, it ran irrigation through the Oval Lawn in front of the Hatch Shell, so that “when people are sitting for concerts, they’re sitting on a beautiful green space and not a mud pit,” Mergel said.

The association’s biggest project yet, and the one Mergel is most excited for, is currently underway. This fall the association will open its new Charlesbank campus and Smith Family Pavilion across from Mass General. According to the Esplanade Association website, the $20-million-value two-acre site will be a “universally accessible space designed for recreational, civic, artistic, educational, and cultural activities.”

“That will really transform people’s access to the park,” Mergel said. “We’ll have year round restrooms, year round water, year round shelter across temperatures and weather conditions. If there’s lightning and the kids in the Teddy Ebersol [baseball] fields nearby need some shelter, we can be there. It’s going to be a game changer.”

Improving access to the park is also what the association plans to focus on in the future. One example Mergel gave was to provide school bus transit grants, so that visitors could bring a school bus of kids and have the funds to park that bus at a nearby lot. But there are also concrete projects the association wants to take on that are driven by community input.

“There is a space behind the Arthur Fiedler Memorial that we call Fiedler Field,” Mergel said. “That space still has bits of asphalt and debris and compacted crab grass, and it’s not a proper field. We would love to make that a beautiful field with irrigation. There are just parts of the park that we know are beloved, and people would really love for them to be a little bit more inviting.”