As per Wikipedia
Clear Lake is the largest natural freshwater lake in California with 68 square miles of surface area. Lakes have existed at the site of Clear Lake for at least 2,500,000 years, possibly making it the oldest lake in North America. It is located in Lake County, north of Napa County and San Francisco.
What a beautiful photo and view, Bruni. I love it in B&W. It looks great with a black background too. Interesting info that I did not know from Wikipedia too. FAV