McKinnan Gulch is a valley in Marin County, California, United States.
It contains a small stream which descends the western slope of the Bolinas Ridge and drains into Bolinas Lagoon.[1]
Near the head of the gulch is an ore vein (reported in 1955) containing chalcopyrite, galena, pyrite, and calcite.[2]
37°54′46″N 122°39′49″W / 37.912704°N 122.663594°W[3]