Spring grasses carpet the valley in the Carrizo Plain; roughly 50 miles (80 km) long and up to 15 miles (24 km) across. Contains the 250,000 acre (1,012 km²; 101,215 ha) Carrizo Plain National Monument (Est. 1/17/2001), largest single native grassland (San Joaquin Valley biogeographic province) remaining in California. Temblor Range in background. San Luis Obispo County, CA.