The Sierra Madre is a mountain range in southwestern California. It forms the southernmost part of the California Coast Ranges and lies mostly in Santa Barbara County, with a small portion extending into Ventura County. The Sierra Madre has a northwest-to-southeast orientation, bordered on the north and northeast by the Cuyama River and Cuyama Valley, and on the south and east by the drainage of the Sisquoc River.

The Coast Ranges of California span 400 miles (644 km) from Del Norte or Humboldt County, California, south to Santa Barbara County. The other three coastal California mountain ranges are the Transverse Ranges, Peninsular Ranges and the Klamath Mountains.