Philadelphia Mountain is a commonly seen peak in a popular hiking area along Highway 2 in Snohomish County, Washington. But even with this distinction, Philadelphia Mountain tends to be greatly underestimated and underappreciated. Some of this might be due to its low elevation and apparent lack of viewpoints as opposed to its more-popular neighbor peak, Mount Index. However, the standard route leading to the summit of Philadelphia Mountain is a fairly straightforward approach.
Although much of Philadelphia Mountain, including the summit, is covered by thick evergreen forests mixed with some old-growth Douglas fir trees, numerous great viewpoints are found throughout the upper ridgeline of the mountain. From the summit area, alone, views extend far both to the north and south. Many peaks located north along the Mountain Loop Highway, north and east in Wild Sky Wilderness, and south into the Alpine Lakes Wilderness (but north of I-90) can be seen from this mountain's great location for far-ranging viewpoints. One of the best views of the North Fork & South Fork Skykomish Rivers joining together can be seen from the mountaintop, with an especially awe-inspiring view of Sunset Falls along the South Fork Skykomish River.
The route to the Philadelphia Mountain summit begins by following the Lake Serene Trail to Lake Serene. This trail is YDS Class 1, but is considered a strenuous maintained trail for many hikers. After arriving at the lake, prospective summiters need to turn uphill east/southeast and head off-trail up steep western slopes of Philadelphia Mountain. The rest of the route to the summit is at worst YDS Class 2, but is still most recommended to attempt in May or June when snow still covers the thick underbrush of the forest and avalanche dangers have typically passed. The route ascends approximately 800' elevation in the first 0.5 miles of the off-trail slope traverse from Lake Serene, before ascending 1000' elevation during the next 1.0 miles to the summit.
1a) If heading east along Highway 2 from Gold Bar, drive 0.2 miles east of MilePost-35 to the Mount Index Road (south side of Highway 2).
1b) If heading west along Highway 2 from Index, drive 0.4 miles west of the Index turnoff to the Mount Index Road (south side of Highway 2).
2) Drive east/southeast along Mount Index Road for 0.25 miles.
3) Turn right (south) and park in the large parking area for the Lake Serene Trailhead.
4) Follow the Lake Serene Trail for 3.6 miles to Lake Serene.
5) From the outlet of the lake, head southeast (off-trail) up the western slopes of Philadelphia Mountain.
6) Hike east/southeast up to the ridgeline and then continue east to the summit (4258' elevation) of Philadelphia Mountain. The off-trail hike from the lake to the summit is 1.5 miles, each way.
TOTAL ROUNDTRIP HIKING DISTANCE: 10.2 miles
Red TapeA Northwest Forest Pass (parking permit) is required for parking at the Lake Serene Trailhead.
CampingBackcountry camping is allowed in the area, but not within 0.25 miles of Lake Serene. There are several flat open areas on the west side of Philadelphia Mountain which would make great backcountry campsites.
Ask a local ranger station about current/local fire restrictions before planning any overnight trips or making any campfires.