Coolidge Dam impounds San Carlos Lake in the San Carlos Indian Reservation. The project irrigates 100,000 acres (400 km²). Coolidge Dam was designed and constructed by the Bureau of Indian Affairs (BIA), which also owns and operates it. The dam was built between 1924 and 1928. The overall structure used of concrete and consists of three domes, which are supported by massive buttresses on centers. It rises , with a crest length of . Two uncontrolled ogee crest spillways are concrete lined and located on each abutment.
San Carlos Lake is seldom full except in unusually wet periods. When former President Coolidge dedicated the dam, Cherokee humorist Will Rogers looked at the grass in the lake bed, and said, “If this were my dam, I’d mow it.”