The Rams were originally founded as the Cleveland Rams in Cleveland, Ohio, in 1936. They played there until 1945, winning the NFL Championship in 1945. In 1946, the team moved from Cleveland to Los Angeles to grow their brand and popularity on the West Coast. They remained in Los Angeles until 1994, then moved to St. Louis and became the St. Louis Rams from 1995 to 2015. The Rams returned to Los Angeles in 2016, where they currently play.
In summary, before being in Los Angeles, the Rams were based in Cleveland, Ohio.