Shaver Lake is one of those hidden gems you are able to experience only because locals take you there or tell you about it. The lake and the town of the same name are about one hour east of Fresno, circa 60 kilometers or 40 miles, and lie in the midst of the Sierra Nevada between Yosemite National Park and Sequoia National Park. Its much more famous neighbors most probably are the reason why not so many tourists but mostly locals come here. Shaver Lake (at 1.500 meters or 5,000 feet altitude) and its brother Huntington Lake (2.100 meters or 7,000 feet) are both artificial. The former being fed by Stevenson Creek and several smaller streams and being part of the Southern California Edison's Big Creek Hydroelectric Project.
Come here if you want to relax. Rent a cabin or stay in the small village. Several trails are waiting to be explored. If you're lucky you're able to rent a pontoon boat in order to cruise on the lake. I can't stress how breathtaking the scenery is. During the week it's usually less crowded but in general you'll always find a spot where you can hang out at the lake without too many spectators and if you're hiking anyway. Take a look at the pictures and the map and be sure to mark this spot for your future trip to California!
Shaver Lake may not be a qualified dark-sky preserve but stargazers will get their money's worth, see the following timelapse of the night sky of Shaver Lake.