Folsom Lake is a reservoir on the American River in the Sierra Nevada foothills of California, United States. Located within Placer, El Dorado, and Sacramento Counties, it is about 25 mi (40 km) northeast of Sacramento. The lake surface area is 11,500 acres (4,700 ha), its elevation is 466 ft (142 m), and it has 75 mi (121 km) of undulated shoreline.

Sacramento County is a county located in the Central Valley region of the U.S. state of California. Its county seat is Sacramento, which is also the state capital. As of the 2020 census, the population of Sacramento County was approximately 1.5 million people, making it the sixth-most populous county in California.