Lake Hemet Dam, located in Mountain Center, California, impounds the South Fork of the San Jacinto River and creates Lake Hemet.

The dam and lake are surrounded by the San Bernardino National Forest.

The dam is operated by the Lake Hemet Municipal Water District, which supplies water to parts of the cities of Hemet and San Jacinto as well as the Garner Valley community of Mountain Center.

The dam was constructed with Portland cement due to its ability to set underwater; however, Portland cement was not available in the western United States at the time of construction.

It was then shipped by railroad to San Jacinto where it was loaded onto mule-drawn wagons to be transported up the mountain.