The beach is about 1000 feet (305 m) long and 200 feet (61 m) wide, with coarse sand and several large boulders. There is a parking lot at the beach, which is then accessible via a footbridge.
Muir Beach is a census-designated place (CDP) in Marin County, California, United States.
Muir Beach is unincorporated, receiving general government services from Marin County, including law enforcement, land use planning, library, public health, and code enforcement. A special district, the Muir Beach Community Services District, provides local services, including fire protection, water, road maintenance, and recreation. The District has a board of directors, with five members elected to four-year terms. The District includes all of the Muir Beach CDP, plus Green Gulch Farm.