In a Monday article for Slam Magazine, Russell explained the Celtics organization was one "of good people," but he "cannot say the same about the fans or the city" of Boston.
Warning: Uncensored racist terms of abuse follow
He wrote: "During games people yelled hateful, indecent things: 'Go back to Africa,' 'Baboon,' 'Coon.' 'Nigger.'"
Russell noted that he "refused" to let the racist taunts from fans harm him: "As far as I was concerned, I played for the Boston Celtics, the institution, and the Boston Celtics, my teammates. I did not play for the city or for the fans."
The Celtics have a place in NBA history as one of the teams to first break racial barriers in the league.
Per Marc J. Spears of The Undefeated, Chuck Cooper became the first Black player drafted into the NBA when the Celtics took him in 1950. Cooper, Nat Clifton of the New York Knicks and Earl Lloyd of the Washington Capitols broke the league's color barrier during the 1950-51 season.
Originally selected No. 2 overall by the St. Louis Hawks in 1956, Russell was traded to the Celtics for Cliff Hagan and Ed Macauley on draft night.
The Celtics became the first team in NBA history to have an all-Black starting five when Russell, Willie Naulls, Satch Sanders, Sam Jones and K.C. Jones played together on Dec. 26, 1964, against the Hawks.
During Russell's playing career, he also became the NBA's first Black head coach, starting in 1966. He won two of his 11 career titles as a player-coach in 1967-68 and 1968-69.