Mountain Center lies just north of Lake Hemet, midway between Hemet and Palm Desert, just south of the town of Idyllwild, and it is southeast of the city of Riverside, the county seat of Riverside County.

[2] Although Mountain Center is unincorporated, it has a post office, with the ZIP code of 92561.

[6] According to the United States Census Bureau, the CDP covers an area of 1.9 square miles (4.9 km2), 99.91% of it land, and 0.09% of it water.

Lake Hemet is the only major body of water in Mountain Center.

Federal: State: Local: Forest Folk, using a grant from the Riverside County Transportation Commission, operates the Idyllwild Shuttle, which provides door-to-door service.