Eden Vieira / Shutterstock
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Senior Staff Writer
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March 2, 2026
Did you know that California’s Clear Lake is 480,000 years old, making it one of the oldest lakes on the continent?
This massive prehistoric lake lies just a few hours from San Francisco, but most of those who drive by have no idea about its remarkable history.
Here’s a closer look…
California’s prehistoric lakes
While the Great Lakes may be the country’s most famous bodies of freshwater, they’re “only” 10,000-15,000 years old, having formed at the end of the last Ice Age.
By comparison, California’s Clear Lake is 480,000 years old, with a basin holding earlier lakes for an estimated 2.5 million years. It’s also the largest natural freshwater lake entirely within California, with an impressive 68 miles of surface area.
California State Parks, CC BY-NC-ND 2.0, via Flickr
Clear Lake was long thought to be the oldest lake in North America, but paleolimnologic research has since redesignated that title to Lake Tahoe, whose uninterrupted history dates back 2.3 million years. In fact, Tahoe is the third-oldest lake in the world behind Lake Baikal in Russia and Lake Tanganyika in Africa.
California’s Mono Lake also dates back 760,000 years, although its sediment record was broken due to volcanic activity.
Visiting Clearlake, California
Clear Lake is found in the aptly-named city of Clearlake, California, which is known for its perennial sunshine.
The lake itself is divided into three arms: Upper, Oaks, and Lower. All of them offer a great range of recreational activities, from camping in the state park to swimming and watersports.
For anglers, Clearlake is sometimes called the “Bass Capital of the West,” offering a great population of largemouth bass.
You can reach Clearlake from San Francisco in less than 3 hours by car via US-101 and CA-29 N.