Mother Mountain is a ridge-like, multi-summit peak in Mount Rainier National Park that rises above 6,480 feet and extends about 3 miles in the Cascade Range northwest of Mount Rainier. Its name comes from a woman-like silhouette visible along the ridge’s northeast summit and was officially adopted in 1913. In 1938, Maynard Miller and H. Kinzner made the first recorded ascent of Second Mother Mountain, a subsidiary summit. The mountain was formed by successive lava flows more than 25 million years ago, and large cirques on its north side reflect substantial Pleistocene glaciation. Its runoff drains toward the Carbon and Mowich river systems.