The hike features an abundance of many species of wildflowers (in season), deep and clear lakes for camping and swimming, and, from the summit of Mount Eddy, outstanding views of Mount Shasta, the Trinity Divide, the Trinity Alps, and many other mountains in far northern California.
Even on hot summer days, it can be cold and windy on the summit, so be prepared with extra clothes.
The Parks Creek Trailhead is a gravel parking lot on Forest Road 17 (42N17) with room for 10+ vehicles but with no amenities or potable water. From here, take the Pacific Crest Trail (PCT) as it goes south from the southern end of the parking area. The PCT contours south and then west, crosses an old logging road in 0.7 miles, then continues to cross a spring-fed stream 1.5 miles from the trailhead. This and other seasonal streams you'll cross in this section may or may not have water in them depending on the time of year. Any water available from them should be filtered or treated.
At 2.9 miles from the trailhead, you reach the start of the Upper Deadfall Meadows, cross Deadfall Creek, and soon reach a four-way trail junction. The PCT continues straight ahead. A right (northwest) turn here would put you on the Deadfall Trail (#6W05) going down past Lower Deadfall Lake (Lake 7139) to the Deadfall Meadows Trailhead on Forest Road 17 (this lower trailhead is an alternative way to reach Mount Eddy if you want more elevation gain in your trip). Instead, you want to turn left (southeast) here and proceed uphill on the Sisson-Callahan National Recreation Trail
Middle Deadfall Lake (Lake 7259) is just off to your right 0.2 miles up the Sisson-Callahan National Recreation Trail
from the four-way junction. At 3.7 miles, after an abrupt climb, you'll reach the first (Lake 7743) of the three Upper Deadfall Lakes, with its three campsites.
At 3.9 miles, you'll pass along the shore of the largest (Lake 7790) of the Upper Deadfall Lakes (more campsites) and then continue on the Sisson-Callahan as it ascends to the southwest, providing you with expansive views of the Deadfall Lakes below and the Trinity Alps far off to the west.
You reach Deadfall Summit at 4.2 miles from the trailhead. Here, the Sisson-Callahan continues straight ahead and downhill as a faint tread but you turn left (east) onto the spur Mount Eddy Summit Trail
(#6W25) that climbs to Mount Eddy's summit, which you'll reach after 0.8 miles of relentless, but well-graded, climbing.
From the top, Mount Shasta fills the view to the east, while Black Butte is visible below and in front of Shasta. The Castle Crags can be seen to the southeast, the Trinity Alps to the west, and (possibly, depending on haze and smoke) Pilot Rock to the north. If conditions are exceptionally clear, you might also be able to make out Mount Lassen to the south. After enjoying the view (and maybe lunch), retrace your steps to the Parks Creek Trailhead.
There are Brook and Rainbow trout in the Deadfall Lakes. Fishing is permitted.
The pile of boards on the summit is all that remains of the fire lookout that functioned here from 1912 until 1931; it didn’t collapse entirely until 2002 or so. There is a pit where the old lookout stood which makes a good place to hunker down if the wind is particularly strong and/or cold.