There were at least three class D California State Leagues in operation at some point in minor league baseball history. Two lasted just a single season (1910 and 1929) and the other lasted three seasons 1913 through 1915. The 1910 version was actually class B until June 6, when it became class D. Sacramento and San Francisco dropped out May 31, and Oakland moved to Merced on June 7, which might explain the drop in classification. Then Fresno disbanded June 24, causing the league to cease operations the same day.