High Quality Content by WIKIPEDIA articles! Russian River State Marine Recreational Management Area (SMRMA) and Russian River State Marine Conservation Area (SMCA) are two adjoining marine protected areas in the Russian River estuary area in Sonoma County, California, on the north-central coast of the state. The combined area of these marine protected areas is 1.21 square miles (3.1 km2), with 0.35 square miles (0.91 km2) in the SMRMA and 0.86 square miles (2.2 km2) in the SMCA.