In California's Sierra Nevada west of the main crest, in an inlier in the Carson-Iceberg Wilderness (which means it's accessible by automobile). Judging by the traffic we saw it's a popular fishing area. The left inset shows a view from the other end of the lake, looking back this way; the right inset is looking directly across that end of the lake. The mountain in that pic is the slope on the left. Our trailhead parking was right near here; we weren't fishing!