Seymour Peak is a summit located in Mount Rainier National Park in Pierce County of Washington state. It is part of the Cascade Range and is situated southeast of Cayuse Pass and northeast of Shriner Peak. Its nearest higher peak is Dewey Peak, to the east. Seymour Peak is named for William Wolcott Seymour (1861-1929), mayor of Tacoma, Washington from 1911 to 1914. He was also a philanthropist, mountaineer, and a contributor to the scouting movement. Precipitation runoff from Seymour Peak drains into tributaries of the Cowlitz River.