Mount Horrible is a 5,804-foot summit in the Blue Mountains of southeastern Washington's Asotin County, ranking as the state's 906th highest peak. Its significance lies less in its height than in its vivid name, echoed by nearby Mount Misery. Nineteenth-century pioneers chose both names to capture the harsh conditions they faced on the Grouse Flat, giving the landscape a lasting reminder of the difficulties of travel and settlement in that area.