From Mosquito Lake/Marshy Lakes Road: A pleasant 1.4 mile walk takes you from the gate up to a saddle on the ridge east of Black Rock. Along the way you look across a verdant upper valley of one of the forks of Mill Creek to the dark east face of 7486-foot Black Rock.
A sign on the right side of the road in the saddle indicates an old trail that runs down the north side of the ridge to Big Mill Creek. The PCT is just below a sign to the left of the road.
From Scott Mountain Campground: Beyond a flat the excellent trail makes two long switchbacks and one short one to the top of the first hump west on the ridge. You are apt to see more cow tracks than boot prints on the trail as you continue west through manzanita and open woods on the crest of the ridge. An unusual combination of sugar pines and lodgepole pines appears before you enter a sparse forest of red firs with a lot of windfalls in a saddle farther west.
Mountain mahogany, usually thought of as an eastern Sierra and Great Basin tree, grows on a rocky hump beyond more switchbacks. You cross over to the north side of the ridge in fir forest 2.7 miles from the trailhead, and come out into a near-clearcut that appears to have been logged 15-20 years ago. The Wilderness boundary at the southwest edge of the logged area very effectively points up the difference between"multiple use" and wilderness as you enter red-fir forest again.
From the boundary you circle around the side of a mountain to turn southwest into a saddle 4 miles from the trailhead, where the PCT crosses the crest right beside, but not on, the Mosquito Lake/Marshy Lakes road.
Whichever way you get to the saddle, the Pacific Crest trail drops away from the road immediately after it touches it in the saddle. You won't see the road above the trail again until you cross it 2.1 miles farther on.
As you traverse an open, brushy slope southwest of the saddle, you have excellent view across Tangle Blue Creek canyon to the jumble of peaks beyond, and Grand National Mine hanging on the side of a ridge. Lassen Peak juts above the horizon tar to the east, and the "back" side of Castle Crags can be seen nearer and a little farther north.
Two little streams, crossing the trail .6 mile from the saddle, probably come from the spring up by the road, but grazing cattle have made them unappealing. Another, slightly larger rill a short distance farther on doesn't look any better where it crosses the trail, but it does water a large garden of California pitcher plants on the hillside above.
After rounding, the shoulder of a ridge, you turn west to a crossing of the Marshy Lakes road, 2.1 miles from the saddle. A tiny stream, lined with pitcher plants, runs across a flat west of the road. Again, it doesn't look like very good drinking water. A much larger stream in a ravine 250 yards from the road does look like good drinking water, but you should keep in mind that it is the outlet of Mosquito Lake, where all the people are.
You continue on a level contour from Mosquito Lake creek to the shoulder of a ridge overlooking the upper end of Tangle Blue Creek canyon and the lower end of Marshy Lakes basin. The Marshy Lakes are not yet in sight. The Marshy Lakes road is directly below, and you can see Tangle Blue Lake shimmering in its cirque farther south. Mount Shasta crowns the horizon back to the northeast.
The PCT rises gradually from the shoulder, heading generally west along the north side of the Marshy Lakes basin. A trail connecting Camp Unalayee and Marshy Lakes, marked only by cairns above and below the tread, crosses the PCT one mile from the road crossing, and runs straight on up the hillside.
Another .5 mile along the side of the basin brings both Marshy Lakes into view below. Upper Marshy Lake is indeed surrounded by marshes.
A large amount of effort was expended in building the PCT along this steep sidehill. Large rocks have been moved to avoid steep detours. Brush has been cut back 3 feet on both sides of the tread. Where the trail crosses talus slides, the tread has been blasted, dug out and leveled, and dirt has been hauled in to cover the broken rock. It is a first-class trail. Time will tell whether it will be maintained as well as it was built.
Metasedimentary rock here is rosy red to rust-colored on the surface, but when broken is dark blue-gray to indigo, mixed with pieces of light blue and white.
As you turn southwest around the head of a basin, a trail from Marshy Lakes, marked by signs on a large tree, crosses the PCT on its way across the crest to East Boulder Lake. The crest is only 200 yards up the little-used trail, and East Boulder Lake is .6 mile down the north side. Even if you don't want to make a side trip all the way to the lake, going up to the crest to look at the wide open basin in which the lake sits is well worth your time. Three little ponds, surrounded by meadows as green as billiard-table felt, sit on a wide shelf one-quarter mile below the crest, and a long strip of grass runs up through red-rock strata almost to the crest farther west. Bordered by more meadows, 32-acre East Boulder Lake fills the lower end of the basin below a drop-off.
East Boulder Lake gets quite a lot of traffic from the north side because a road comes within 2 miles, but it still harbors some very large eastern brook, rainbow and brown trout. The only drawback to this otherwise delightful basin can be the large number of cattle that sometimes graze in it.
The PCT continues its contour around the head of the Marshy Lakes basin through rough terrain behind some knobs and across the face of the cliffs where the tread has been blasted out of the rock. A beautiful little spring trickles down the rocks beside the trail .3 mile from the East Boulder Lake trail, the first water that looks safe since leaving the trailhead.
At the end of the contour around the basin, you are headed almost east, and then you climb moderately south to the top of the spur ridge between Marshy Lakes and Eagle Creek canyon, 7 miles from the trailhead at the locked gate. The trail turns west from this crest to ascend moderately across another spur ridge and along the side of the main ridge through brush, open forest and talus slides. Several small ponds are on a wide bench .25 mile below the trail, offering a good place to camp if you want to stop now.
After rounding the shoulder of another spur ridge, you come to a trail junction right on top of the Scott River divide, 2.4 miles from the East Boulder Lake trail junction. The trail north from here goes down the divide slope to Middle Boulder Lake, and the PCT now follows most of the course of an old trail that ran southwest down to the divide between Eagle Creek and Granite Creek. A trace of the old trail drops below the PCT as it turns southwest from the Scott River summit, but it doesn't go anywhere.
Middle Boulder Lake is a repeat of East Boulder Lake on a smaller scale. Two little ponds are on a bench just below the summit, and Middle Boulder Lake is almost a mile below them. The basin isn't as big, nor is it as verdant. Middle Boulder Lake, despite what the Forest Service Trinity Alps Wilderness map indicates, is inside the boundaries of Trinity Alps Wilderness.
You descend from this divide through a forest of foxtail pines that changes to red firs as you go farther down the side of the ridge. The trail skirts the edges of two meadows, then rises slightly and runs straight across a third meadow where you look up at 7790-foot Eagle Peak. The trail to Telephone Lake is in the trees along the upper, southwest edge of this meadow. The junction with it .4 mile from the Middle Boulder trail is not obvious, but it is signed.
Details mentioned in this article were accurate at the time of publication