Mother Mountain is a multi-summit, 3-mile long ridge-like mountain located in Mount Rainier National Park, in Pierce County of Washington state. It is part of the Cascade Range, and lies northwest of the summit of Mount Rainier. The Wonderland Trail provides one approach option to this mountain, and the summit offers views of Mount Rainier. East Fay Peak is its nearest higher neighbor, to the south. Precipitation runoff from Mother Mountain is drained by Cataract Creek on the south side of the mountain, and Ipsut Creek drains the north side of it, and both are tributaries of the Carbon River. The west side drains into Mowich Lake, and thence Mowich River.