French Lake Reservoir (National ID # CA00247) is a reservoir in Nevada County, California. The earthen, rock-fill French Lake Dam was first constructed in 1859, and is a candidate for the first use of rock-fill in an engineered dam.. Reconstructed in 1948, it impounds Canyon Creek for flood control, irrigation water storage, municipal drinking water, and hydropower. The dam is 100 feet high, with a length of 300 feet at its crest. The owner and operator is the Nevada Irrigation District, one of its ten facilities.
The reservoir has a surface area of 337 acres, with a maximum capacity of 13,800 acre-feet. The site is surrounded by Tahoe National Forest. The adjacent namesake townsite of French Lake, California is a ghost town of the California Gold Rush era.