Mountain Center is an unincorporated community in west central Riverside County, California, United States. It lies along State Route 74 in the southern division of San Bernardino National Forest, just north of Lake Hemet. Mountain Center lies midway between Hemet and Palm Desert, and it is southeast of the city of Riverside, the county seat of Riverside County. Its elevation is 4,518 feet (1,377 m), and it is located at (33.7041889, -116.7258522). Although Mountain Center is unincorporated, it has a post office, with the ZIP code of 92561.
According to the 2000 Census, Mountain Center had a population in 2000 of 1,495. The community is 85.2 per cent white, 11.5 per cent Hispanic, 5.4 per cent American Indian, and 0.9 per cent Asian. Non-Hispanic whites represent 82.2 per cent of the population