Humpback Mountain, Mountain summit in King County, United States.

Humpback Mountain is a 5,174-foot (1,577 m) peak in the Cascade Range, in King County, Washington. It lies in the marine west coast climate zone of western North America, where Pacific fronts forced upward by the Cascades drop heavy rain and winter snow on the west side.

Humpback Mountain rises to 5,174 feet (1,577 m) in the Cascade Range of King County, Washington. Its documented record is essentially geographic: the peak is identified by elevation and by the marine west coast climate of western North America, in which Pacific fronts forced upward by the Cascades drop rain and snow on the range's west side. No dated climbing or ranger-district history is recorded in the sources.

The peak draws outdoor enthusiasts who use it year-round for hiking and scrambling activities. The route appeals to people who enjoy moving through natural terrain and spending time in the mountains.

The mountain is accessed from Interstate 90 by following forest service roads to a parking area near the trailhead. Plan for changing conditions throughout the year, as snow, rain, and wet ground can affect how the route feels.

Humpback Mountain reaches 5,174 feet (1,577 m) in the Cascade Range of King County, Washington. Its position in the marine west coast climate zone means Pacific fronts rise against the range and drop rain or snow, so the west side sees heavy precipitation, especially as winter snowfall. Summer often brings little or no cloud cover.