San Luis Obispo Spanish for St. Louis, the Bishop) is a city in California, located midway between San Francisco and Los Angeles on the Central Coast. Founded in 1772, San Luis Obispo is one of California’s oldest communities. The city, referred to locally as SLO, SLOtown, S.L.O and San Luis, is the county seat of San Luis Obispo County and is adjacent to California Polytechnic State University (Cal Poly). As of the 2006 Census Bureau estimate, the city population was 42,963 (down 2.8% from 2000).