Pyramid Lake, Artificial lake in Los Angeles County, United States

Pyramid Lake is a reservoir on Piru Creek in the western Sierra Pelona Mountains, formed by the 118 m (387 ft) earth and rock Pyramid Dam. It lies on the border of Angeles and Los Padres national forests, west of Interstate 5 south of Tejon Pass. The former US 99 alignment lies below the water, and the lake holds 180,000 acre-feet.

The reservoir was created in 1972 and completed in 1973 as a holding reservoir for the California State Water Project. Its 118 m earth and rock dam, built by the California Department of Water Resources, was finished in 1973. Pyramid and Castaic lakes serve as the upper and lower reservoirs for the 1,495-megawatt Castaic Power Plant. In 1843, gold was found in Santa Feliciana Canyon just south of the dam, but the small find drew only Francisco Lopes of Rancho Temescal and a few ranchers.

The Vista del Lago Visitor Center presents exhibits about California water systems and offers interpretive programs about local natural resources.

The site offers several boat docks and a marina with launch ramps and watercraft rental for those who want to spend time on the water. A visitor center provides information about California's water supply system and the natural conditions of the region.

Pyramid Rock, the landmark that gave the lake its name, was created in 1932 when a ridge was cut through for the Ridge Route Alternate (US 99). The roughly 76-metre rock still stands directly in front of the dam, and the old US 99 alignment now lies submerged below the water.