Ape Canyon is a gorge along the edge of the Plains of Abraham, on the southeast shoulder of Mount St. Helens in the state of Washington. The gorge narrows to as close as eight feet (2.5 m) at one point. The name alludes to a reported encounter with several “apemen” in 1924, an event later incorporated into Bigfoot folklore.
Ape Canyon was heavily impacted by the 1980 eruption of Mount St. Helens. Adjacent to the steep rocky canyon is the present Ape Canyon trail, popular with hikers and mountain bikers. On the south side of the mountain is another feature named Ape Cave.