The Salton Sea is a shallow, landlocked, highly saline endorheic lake in Riverside and Imperial counties at the southern end of the U.S. state of California. It lies on the San Andreas Fault within the Salton Trough, which stretches to the Gulf of California in Mexico. The lake is about 15 by 35 miles at its widest and longest. A 2023 report puts the surface area at 318 square miles (823.6 km2). The Salton Sea became a resort destination in the 20th Century, but saw die-offs of fish and birds in the 1980s due to contamination from farm runoff, and clouds of toxic dust in the current century as evaporation exposed parts of the lake bed.