San Luis Obispo (săn lōˈĭs ōbĭsˈpō) [key], city (1990 pop. 41,958), seat of San Luis Obispo co., S Calif., near San Luis Obispo Bay; inc. 1856. Printing and publishing, machinery, medical goods, electronic equipment, computers, and tourism are important to the economy. In 1846, John Frémont seized the city for the United States. To escape torrential rains he quartered in the Franciscan mission, San Luis Obispo de Tolosa (1772), which is now a state landmark. Many historic buildings are preserved in the mission plaza. The city is the seat of California Polytechnic State Univ., San Luis Obispo. Los Padres National Forest lies to the east.