Trinity Lake, previously called Clair Engle Lake, is a reservoir on the Trinity River formed by the Trinity Dam and located in Trinity County, California, United States. The dam was built by the U.S. Bureau of Reclamation. The lake's capacity is 2,447,650 acre⋅ft, making it one of the largest reservoirs in California. The lake's surface is at 2,370 ft above MSL. Trinity Lak…Trinity Lake, previously called Clair Engle Lake, is a reservoir on the Trinity River formed by the Trinity Dam and located in Trinity County, California, United States. The dam was built by the U.S. Bureau of Reclamation. The lake's capacity is 2,447,650 acre⋅ft, making it one of the largest reservoirs in California. The lake's surface is at 2,370 ft above MSL. Trinity Lake captures and stores water for the Central Valley Project, which provides the Central Valley with water for irrigation and produces hydroelectric power. This lake is known for its many small arms, glassy inlets, and good water-skiing conditions.