A short (4.4-mile) round-trip run from Islip Saddle, up the PCT to the top of Mount Williamson.
Adventure Pass is required to park at the trailhead.
From the parking area at Islip Saddle, head north to join the PCT; the trail immediately begins to ascend a moderate grade. Though this is a short (2.2-mile one-way) trail, runners pay for it with the elevation gain as the trail climbs at a fairly consistent grade. At about 1.6 miles, there is a junction in the trail. The PCT continues straight and a fainter unnamed trail veers off to the right.
Take this fainter trail and begin a steeper ascent of the mountain; the trail gets a little hairy in places. Just below the top, turn right to head up to the summit of Mount Williamson.
From the top, runners will enjoy amazing desert views; playas, buttes, and mountain ridges dot the landscape. The San Andreas Rift Zone lies at the base of the mountain and the Devils Punchbowl, a jumbled mess of sedimentary rocks, lies to the north.
After taking in the views, head back the way you came.
Thanks to John McKinney, The Trailmaster, for sharing this trail description. To learn more about trails in California, check out his guides at The Trailmaster Store
This run is interesting in that it offers runners the shade of pine and fir trees while simultaneously providing amazing views of the desert and its abundant Joshua Trees.
The mountain is named after Lieutenant Roger Stocktan Williamson (a map maker for the U.S. Army) who first explored the area in an effort to find a railroad route through or around the mountains.