Mount Jupiter is a 5,711-foot summit in Washington’s Olympic Mountains, in Jefferson County, within The Brothers Wilderness and managed by Olympic National Forest. Easily recognized from Seattle between The Brothers and Mount Constance, it is especially notable for its dramatic relief, rising about 5,100 feet above the Duckabush Valley in just 1.5 miles. Its north side drains toward the Dosewallips River and its south side into the Duckabush River. Named by the Seattle Press Expedition in keeping with nearby Mount Olympus and Greco-Roman mythology, the name was later officially adopted by the United States Board on Geographic Names. Its marine west coast climate brings heavy precipitation, cloudy winters, avalanche-prone snow, and clearer summers.