Henry W. Coe State Park (HWCSP) is a botanically important preserve in the central interior Coast Ranges of California that until now has been overlooked bryologically. Comprising 177 species including 1 variety and 3 undescribed taxa, the bryophyte flora of HWCSP currently represents 22% of California’s bryophyte diversity. Situated along the Diablo Range, this state park contains relictual taxa from the exterior coast ranges as well as rare and disjunct populations from within California. Thirty species from Santa Clara County and sixty-two species from Stanislaus County are reported for the first time further highlighting the state’s need for bryological surveys.