At least in mid and late summer, there is no water between the creek at 8900 feet and Frog Lake.
The trailhead is at 8070 about 5 miles up the Onion Spring OHV Route.That road is rated easy for vehicles with good clearance and 4-wheel drive. If you don't have 4-wheel drive, you can run up the road. I was not the only one who did this, because as I was running down the road I met a pair of backpackers running up.
From the trailhead, the trail climbs steadily up the hill under a coniferous forest. At 8,900 if crosses a stream, which in mid-season is the last water source before Frog Lake. There is a nice, sheltered little campsite here. The trails climbs up along the top of a ridge through a beautiful Juniper forest. By 10,000 feet, we move out from under the trees with continually increasing views of the surrounding mountains. At just over 4 miles we reach the high point of about 10,550 feet. From there we have a 270 degree panorama of much of the Ansel Adams Wilderness. On a clear day, the views would be spectacular.
The USGS topo map shows Arch Rock
as being below the trail just before the high point. This is incorrect. To reach the arch, continue north. The trail drops about 250 feet and then climbs about 40 feet to another saddle. At this saddle, the arch is partially visible. It is about 75 yards to the left (southwest) up an easy sandy trail. It is a good place to camp. There is a wide area that is relatively flat and sheltered by large rock formations. No fires are allowed, and there is no water. See the "Arch Rock
" Gem for more details.
From Arch Rock
, the trail drops until at 5.1 miles and 8800 feet it meets the Rock Lake Trail #26E02, which heads west towards Rock Lake. The Margaret Lakes trail wanders around ridges with minor ups and down for about 1/2 mile to Frog Lake. This beautiful lake with great campsites would make a good running target itself, but, if you have gone this far, you really should head on to Big Margaret and Rainbow Lakes, the most superb lakes in the area. Coyote Lake has good fishing and is also worth a visit.