State Route 27, commonly known by its street name Topanga Canyon Boulevard, is a state highway in the U.S. state of California that runs from the Pacific Coast Highway at Topanga State Beach near Pacific Palisades, through the Topanga Canyon in Topanga, and continuing through Woodland Hills, Canoga Park, West Hills, and Chatsworth to the Ronald Reagan Freeway.

Topanga is an unincorporated community in western Los Angeles County, California, United States. Located in the Santa Monica Mountains, the community exists in Topanga Canyon and the surrounding hills. The narrow southern portion of Topanga at the coast is between the city of Malibu and the Los Angeles neighborhood of Pacific Palisades. As of the 2020 census the population of the Topanga CDP was 8,560. For statistical purposes, the United States Census Bureau has defined Topanga as a census-designated place (CDP). 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.