Lagunitas is an unincorporated community in Marin County, California. It is located 10 miles southwest of Novato, at an elevation of 217 feet. For census purposes, Lagunitas is aggregated with Forest Knolls into the census-designated place Lagunitas-Forest Knolls.The first post office at Lagunitas opened in 1906. Lagunitas' ZIP Code is 94938.