Atascadero is a city in San Luis Obispo County, California, United States, located on U.S. Route 101. Atascadero is part of the San Luis Obispo-Paso Robles metropolitan statistical area, which encompasses the extents of the county. Atascadero is farther inland than most other cities in the county, and as a result, usually experiences warmer, drier summers, and cooler winters than other nearby cities such as San Luis Obispo and Pismo Beach. The main freeway through town is U.S. 101. The nearby State Routes 41 and 46 provide access to the Pacific Coast and the Central Valley of California.

San Luis Obispo County, officially the County of San Luis Obispo, is a county on the Central Coast of California. As of the 2020 census, the population was 282,424. The county seat is San Luis Obispo.