San Anselmo is an incorporated town in Marin County, California, in the western United States. It is located about 20 miles (32 km) north of San Francisco. Neighboring towns include San Rafael to the east, Fairfax to the west, and Ross to the south. Mount Tamalpais dominates the view to the south. The population was 12,378 at the 2000 census. Among its notable inhabitants are Michael Jantze and George Lucas.
Most of the downtown antique and boutique stores and restaurants, for which San Anselmo is well known, are along the banks of San Anselmo Creek. Heavy rains caused the creek to flood in 1982, as well as recently on December 31, 2005.