California has over 3,000 named lakes, natural and artificial, but there is no doubt some lakes are better suited for an afternoon on the water than others. Of all the lakes across California, it is the state’s most famous that is also the cleanest. Lake Tahoe, which straddles the Northern California-Nevada border, is one of the cleanest lakes in the US, and the absolutely cleanest lake in California. There are a number of amazing facts to know about Lake Tahoe. Considered one of the largest Alpine lakes in North America, Lake Tahoe spans 22 miles long by 12 miles wide. At 1,645 feet deep, it is also the second-deepest lake in the US, coming second only to Oregon’s Crater Lake.