Bismarck Peak is a mountain summit centrally located in the William O. Douglas Wilderness on land administered by the Wenatchee National Forest. It is also 24 miles east-southeast of Mount Rainier in Yakima County of Washington state. Bismarck Peak is situated east of the crest of the Cascade Range, southeast of Bumping Lake, south of Mount Aix, and northwest of Rimrock Lake. Its nearest higher peak is Mount Aix, to the north-northeast. Aix and Bismarck are the two highest peaks midway between Mount Rainier National Park and Yakima, Washington so they are quite prominent. Precipitation runoff from Bismarck Peak drains into tributaries of the Yakima River, thence into the Columbia River.