Location Nestled in the foothills of Lake County, just 2-1/2 hours north of San Francisco, and 2 hours northwest of Sacramento, you will find Clear Lake...California's largest natural fresh water lake. Clear Lake has more than 100 miles of shoreline that has changed little in the last 10,000 years. That is because it is a natural lake and can't be drawn down below normal level, as can lakes created for power and irrigation.