Stinson Beach is an unincorporated community and census-designated place (CDP) in Marin County, California, on the west coast of the United States. Stinson Beach is located east-southeast of Bolinas, right across the channel that terminates the bay mouth bar of the Bolinas Lagoon. at an elevation of 26 feet (8 m). The population of the Stinson Beach CDP was 541 at the 2020 census.

Marin County is located in the northwestern part of the San Francisco Bay Area of the U.S. state of California. As of the 2020 census, the population was 262,231. Its county seat and largest city is San Rafael. Marin County is across the Golden Gate Bridge from San Francisco, and is included in the San Francisco–Oakland–Berkeley, CA Metropolitan Statistical Area.