Castaic Lake State Recreation Area, State recreation area in Los Angeles County, US.

Castaic Lake State Recreation Area is a state park in Los Angeles County, California, built around two reservoirs: the main upper lake and the smaller Afterbay below it. The site has boat launches, picnic areas, swimming sections, and open shoreline spread across both water bodies.

Castaic Lake is a reservoir formed by Castaic Dam on Castaic Creek, and the surrounding 4,224-acre park was established in 1965 under the California Department of Parks and Recreation. The lake serves as the terminus of the West Branch California Aqueduct, and the Elderberry Forebay Dam bisects it, creating the adjacent Elderberry Forebay that feeds the Castaic Power Plant.

Castaic Lake takes its name from the Chumash word Kaštiq. Its shoreline has stood in for other worlds on screen: the lake was a main filming location for Mighty Morphin Power Rangers, and scenes were shot here for VR Troopers, Masked Rider and Beetleborgs. The lower lagoon's swim beach opens from Memorial Day weekend to Labor Day weekend.

The upper lake and the Afterbay each have separate entry points, so it helps to check which section suits your activity before heading out. Parking fills up quickly on summer weekends, so an early arrival makes the visit more comfortable.

Castaic Lake's water comes from Pyramid Lake through the Angeles Tunnel and drives the Castaic Power Plant, a pumped-storage facility at the northern end of Elderberry Forebay; the turbines are powered by the water rather than pumping it uphill. The lake was also the starting point for The Amazing Race 26 on November 12, 2014, and Baby Keem's debut album The Melodic Blue used a photo taken here for its cover.