Dozens of volunteers gathered Saturday to participate in the largest veteran outreach projects in Boston.

Operation Thank a Vet was started in 2015 by the city’s Office of Veterans’ Services. The goal of the outreach program is to not only thank veterans for their service, but to also provide information about resources they may need.

Volunteers met at the Brighton Marine Health Center and then spread across the Allston-Brighton area to knock on veterans’ doors.

“I think it brings back a sense of accomplishment and camaraderie,” said Bob Notch, Brighton Marine’s program development officer and a retired Army colonel with 27 years of active service. “You see their faces light up when you thank them for their time in service.”

So far, 4,000 of the 22,000 veterans in Boston have been reached through the program.