Mammoth Lakes, California. Mammoth Lakes is a town in Mono County, California, the county's only incorporated community. It is located 9 miles (14 km) northwest of Mount Morrison, at an elevation of 7,880 feet (2,400 m). As of the 2010 United States Census, the population was 8,234, reflecting an increase of 1,141 from the 7,093 counted in the 2000 Census.