OverviewKeystone Mountain is a very remote summit in the depths of the western slopes of the northern Sierra Nevada, approximately 40 miles northwest of Lake Tahoe. There is nothing of interest to note about this mountain; it is located in the midst of an active logging area of the Tahoe National Forest. Getting to the summit requires little physical work, but a lot of navigating forest and logging roads. This is a very sparsely visited area, so a visit to Keystone Mountain means solitude. Even though Sierra City and Highway 49 are located a few miles from the summit, the former are about 3000 feet below steep canyon walls. The roads to this area are not plowed in the winter, so unless you want to snowshoe or cross country ski about 40 miles roundtrip, Keystone Mountain is only accessible during the warmer months of the year. The views from the summit are supreme. The Sierra Buttes command the scenery to the north, and many peaks around Lake Tahoe can be seen to the south and southeast. The views east and west consist of typical Sierra Nevada upper montane forests, stretching seemingly forever.
Getting ThereNote: the roads to Keystone Mountain are in decent-to-mediocre shape, perhaps something between a 2 and a 3 on this scale.
From Nevada City, California, take Highway 49 north towards Downieville for about 18 miles. Take a right on Ridge Road, signed Pike and Alleghany. Follow Ridge Road for about 16 miles to a weird little intersection. Make a left onto Mountain House Road, and then a quick right onto Pliocene Ridge Road. If you begin to descend down the hill, you've missed the turn. In a little over 8 miles, the pavement ends at a junction. Take the right hand fork (the left hand fork also will lead you there, but there are more junctions that way). The right hand fork is Henness Pass Road, also known as Sierra County Road 301. Take this road for just over 6 miles, staying on the main road, to a spot called Keystone Gap, which has the first great view of the Sierra Buttes, as well as a view of the east face of Keystone Mountain. Here the road makes a sharp right turn to follow the ridge. Instead, make a sharp left turn up the hill onto an unsigned logging road.
Follow the smoother logging road about 1.3 miles to a junction, where you should continue straight. Park at the next bend in the road, perhaps 75 yards past that junction. Here you should see an old logging road heading uphill to the right, blocked by some brush, rocks, and berms. From here it is about .5 miles and 400 feet of vertical gain to reach the summit benchmark.