The NBA expanded to 17 teams as the Portland Trail Blazers, Buffalo Braves, and Cleveland Cavaliers began play.[2] For the first time, the league was divided into Conferences (East and West), each with two divisions. The Detroit Pistons and Milwaukee Bucks were shifted from the old Eastern Division to the Western Conference's Midwest Division, and the Atlanta Hawks were switched from the Western Division to the Eastern Conference's Central Division.
Before the season, on June 18, 1970, the NBA owners voted 13–4, to seek approval from Congress for a merger with the 11-team American Basketball Association into a 28-team league that would retain the NBA name.[3] The NBA players opposed the merger, and Oscar Robertson filed an antitrust lawsuit that prevented further proceedings.
In only their third year of existence, the Bucks won the NBA Championship, sweeping the Baltimore Bullets in four straight games. This was the first NBA finals to feature none of the NBA's foundation franchises; the Bullets franchise had joined the NBA as the Chicago Packers in 1961, and the Bucks franchise had joined in 1968. It was also the first NBA finals since 1956 to feature neither Bill Russell or Wilt Chamberlain.