1928
Riverside, California, USA
The founded date is the earliest mention.
"At the second meeting of the Amateur Movie Club of Riverside, Calif., "Vienna," produced by the Austrian Amateur Movie Club and "The Norfolk Case," filmed by the Motion Picture Club of New Haven, Conn., were screened." (Gale 618)
References:
Gale, Arthur L. "Amateur Clubs," Movie Makers 3, no. 7 (1928): 456:457, 482:485.
Gale, Arthur L. "Amateur Clubs," Movie Makers 3, no. 9 (1928): 578:579, 617:619.
Gale, Arthur L. "Amateur Clubs," Movie Makers 3, no. 12 (1928): 780:781, 819:821
Gale, Arthur L. "Amateur Clubs," Movie Makers 4, no. 7 (1929): 446:447, 471:474.