Mount Aix is a 7,766-foot summit in central Washington within the William O. Douglas Wilderness and Wenatchee National Forest. East of the Cascade crest, it is the highest point in the wilderness and the most prominent peak in a wide area east of Mount Rainier National Park and north of the Goat Rocks. Part of the Mount Aix Volcanic Complex, it reflects the volcanic origins of the Cascade region, and its runoff feeds tributaries of the Yakima River and then the Columbia. On the drier east side of the Cascades, it gets less precipitation than western peaks. Its officially recognized name dates to 1897, after earlier maps used Mount Aiks.