Bon Tempe Lake, Reservoir in Marin County, California, United States

Bon Tempe Lake is a reservoir in Marin County's rolling hills, surrounded by dense forests of redwoods, Douglas firs, and oak trees. The lake covers about 140 acres and is held back by an earthen dam that collects water from Lagunitas Creek.

Bon Tempe Lake was created in 1948 by the earthen Bon Tempe Dam on Lagunitas Creek, built by the Marin Municipal Water District. The reservoir flooded the ranch and dairy of the Bautunpi brothers, whose surname was Americanized as Bon Tempe. Alpine Lake lies beneath its dam, and Lake Lagunitas sits immediately to the east.

The name Bon Tempe is an Americanization of the Bautunpi family name; the Bautunpi brothers ran a ranch and dairy that was removed when Bon Tempe and Alpine reservoirs were created. The reservoir is managed by the Marin Municipal Water District, and rainbow trout, largemouth bass and smallmouth bass are caught in its water.

The lake sits about 720 feet (220 meters) above sea level and is best visited early in the morning or during off-peak times when fewer people are present. Parking lots can fill quickly on weekends, so arriving early or visiting on weekdays is recommended.

Bon Tempe is the widest lake in the Mount Tamalpais watershed, and it lies on Lagunitas Creek; Alpine Lake sits directly beneath its dam, while Lake Lagunitas is immediately to the east. The California Office of Environmental Health Hazard Assessment warns against eating fish caught here because of elevated mercury.