Cal Fire San Luis Obispo

San Luis Obispo County, officially the County of San Luis Obispo, is a county on the Central Coast of California. Its population was 282,424 at the 2020 census, and the U.S. Census Bureau estimated 282,367 residents on July 1, 2025. San Luis Obispo is the county seat and its largest city by population. The county has 3,301 square miles (8,550 km2) of land, extending from the Pacific coast across the Santa Lucia Range to inland valleys and the Caliente Range.