Mount Mystery is a prominent mountain summit located in the Olympic Mountains in Jefferson County of Washington state. It is located within Olympic National Park on the Olympic Peninsula. Mount Mystery is the sixth-highest peak of the Olympic Mountains, after Mount Olympus, Mount Deception, Mount Constance, Mount Johnson, and Inner Constance. Its nearest higher neighbor is Mount Deception, to the north-northwest. Little Mystery (6941 ft) is a subsidiary summit south of Mount Mystery.