American music legend Pete Seeger turns 90 on May 3, but the celebrations honoring his musical legacy and social activism will go on throughout the year.

Hudson River Sloop Clearwater, the environmental group founded by Seeger in the 1960s, is marking the birthday and its own 40th anniversary with a series of concerts in the spring and summer. 

Wilco's Jeff Tweedy will play a rare acoustic solo set at Clearwater's annual "Spring Splash" fundraiser in Beacon, N.Y. on March 28.  Tweedy and Seeger will perform together at this sold out event.

Blues singer Susan Tedeschi, folk hero Arlo Guthrie, “newgrass” sensations Old Crow Medicine Show and Alejandro Escovedo are some of the artists headlining the annual Clearwater Festival in Croton, N.Y. on June 20-21. The Persuasions, indie favorites Dr. Dog and Elvis Perkins in Dearland, New Pornographers frontman A.C. Newman,  and Allison Moorer are among the dozens of other performers announced today on the festival's website.

Seeger will be performing numerous times during the two-day festival, and his grandson (and frequent collaborator) Tao Rodriguez-Seeger will also play a set with his band.

On May 3, Seeger's actual 90th birthday, the folk music icon will be feted with a birthday party at Madison Square Garden in New York City.  Bruce Springsteen, Eddie Vedder, and Steve Earle are among the artists who will appear alongside Seeger at the concert. 

All of the money raised at the events support Clearwater’s environmental research, education and advocacy efforts to help preserve and protect the Hudson River. 

Asked last year by Billboard what his legacy will be, Seeger replied, "My family will remember me, and a few others. I'm one of a lot of songwriters. There'll be more important things to think about."