Santa Margarita Lake is a reservoir located in San Luis Obispo County, California. The lake was built in 1941 to provide water for the local agricultural community. It is fed by the Salinas River and the Santa Margarita Creek, which drain from the Santa Lucia Mountains. The lake is also supplied by snowmelt from the mountains. The watershed provides water to surrounding cities, including San Luis Obispo and Atascadero. The lake is a popular recreation area with opportunities for boating, fishing, and camping. The surrounding area is also home to vineyards and wineries, making it a popular destination for wine enthusiasts. The lake is managed by the County of San Luis Obispo Parks and Recreation Department.