Forest Knolls is an unincorporated community in Marin County, California. It is located southwest of Novato, at an elevation of 249 feet (76 m). For census purposes, Forest Knolls is aggregated with Lagunitas into the census-designated place Lagunitas-Forest Knolls.
The first post office at Forest Knolls opened in 1916. Forest Knolls' ZIP Code is 94933.