Lake Casitas is a man-made lake in the Los Padres National Forest of Ventura County, California, created by the construction of Casitas Dam on Coyote Creek, two miles (3 km) before it joins the Ventura River. Santa Ana Creek and North Fork Coyote Creek also flow into the lake. The dam was constructed of earth-fill and was completed in 1959. It is and was built by the United States Bureau of Reclamation. The lake has a capacity of . The dam was built as part of the Ventura River Project and was strengthened in Jun-Dec 2000 as a seismic improvement to help withstand earthquakes greater than 6.5. The project provides drinking water and water for irrigation. A secondary benefit is flood control. In the center of Lake Casitas is 2 km Main Island, whose peak rises more than from the lake surface.