Harmonica Arch, Jefferson County, Colorado
Photo by Jay Wilbur
NABSQNO 13S-465937-4338058. Harmonica Arch is a buttress natural arch eroded through granite. Natural arches in granite are rare, but many examples are found in Colorado. This one is among the longest unsupported spans of granite in the US.
Harmonica Arch is located above Goose Creek in the Lost Creek Wilderness Area of the Pike National Forest, in Jefferson County, Colorado. Access involves a lengthy drive on sometimes rough, dirt Forest Service roads, followed by a 2 to 3 mile hike. Although most of the hike is along the Goose Creek trail, the last half mile involves bushwhacking, a tricky crossing of Goose Creek, and a confusing ascent up the west bank to the arch.
Harmonica Arch gets its name from the streaks of patina that decorate its lintel. It has also been known as Finger Rock Arch after a jointed monolith that is nearby. It has a span of 85 feet, a height of 30 feet, a width of 18 feet, and a thickness of 15 feet.