Who were the original NBA teams?

The NBA originated in 1946 with 11 teams, and through a sequence of team expansions, reductions, and relocations currently consists of 30 teams. The United States is home to 29 teams and one (Toronto Raptors) is located in Canada.

The original 11 teams were: Boston Celtics, Chicago Stags, Cleveland Rebels*, Detroit Falcons*, New York Knickerbockers, Philadelphia Warriors, Pittsburgh Ironmen*, Providence Steamrollers, St Louis Bombers, Toronto Huskies* and Washington Capitols.
* these 4 teams dropped out after one season.

https://en.m.wikipedia.org/wiki/National_Basketball_Association#Creation_and_merger

The NBA was officially named in 1949 after a merger, but considers those first 3 years as part of the NBA.

The 1946–47 BAA season was the inaugural season of the Basketball Association of America. (Following its third, the 1948–49 season, the BAA and National Basketball League merged to create the National Basketball Association or NBA.) The league launched with 11 teams playing a 60-game schedule. The postseason tournament at its conclusion, the 1947 BAA Playoffs, ended with the Philadelphia Warriors becoming the first BAA Champion, beating the Chicago Stags 4 games to 1 in the BAA Finals.

The NBA recognizes the three BAA seasons as part of its own history, sometimes without comment, so BAA 1946–47 is sometimes considered the first NBA season.

https://en.m.wikipedia.org/wiki/1946-47_BAA_season

The Toronto Huskies, Pittsburgh Ironmen, Detroit Falcons, and Clevland Rebels left after the first season of 1946-47. The Providence Stemrollers stayed for three seasons. The St. Louis Bombers and the Chicago Stags both were there for four seasons. The Washington Capitols stayed for five seasons. The Philadelphia Warriors were in for the first 16 seasons until changing to San Fransisco for nine years and Golden State from 1971-72 to present. The Boston Celtics and the New York Knickerbockers are the only teams who have been in the NBA from the beginning to present.

Sorry, I meant to say "Steamrollers".