The route becomes a major city arterial through the valley, intersecting US 101 before entering Warner Center and Canoga Park.

[citation needed] The Topanga Canyon Beach Bus, operated by the Los Angeles County Department of Public Works, runs on the southern portion of SR 27.

[7] A portion of it through Topanga Canyon has been officially designated as a scenic highway by the California Department of Transportation.

[12] Except where prefixed with a letter, postmiles were measured on the road as it was in 1964, based on the alignment that existed at the time, and do not necessarily reflect current mileage.

[1] Segments that remain unconstructed or have been relinquished to local control may be omitted.