Topanga is a census-designated place (CDP) in western Los Angeles County, California, United States. Located in the Santa Monica Mountains, the community lies in Topanga Canyon. The narrow southern portion of Topanga at the coast is in between the city of Malibu and the city of Los Angeles neighborhood of Pacific Palisades. Topanga had a population of 8,289 as of 2010. The ZIP code is 90290 and the area code is primarily 310, with 818 only at the north end of the canyon. It is in the 3rd County Supervisorial district.Topanga CanyonTopanga Creek drains Topanga Canyon and is the third largest watershed entering the Santa Monica Bay. The creek is one of the few remaining undammed waterways in the area, and is a spawning ground for steelhead trout. The area typically receives about 22" of rain annually. Topanga Beach lies on the coast at the outlet of Topanga Creek. Topanga Canyon Boulevard, State Route 27, is the principal thoroughfare, connecting the Ventura Freeway (US 101) with Pacific Coast Highway (SR 1). The southern portion of the boulevard largely follows Topanga Creek. North of the Old Topanga Canyon Road intersection, the boulevard traverses the Santa Monica Mountains.
