Mount Henderson is a 6,003 ft (1,830 meter) mountain summit located in the Olympic Mountains, in Mason County of Washington state. It is situated on the shared boundary of Olympic National Park with Mount Skokomish Wilderness. Its nearest higher peak is Mount Skokomish, to the east-northeast. Precipitation runoff from the mountain drains into the Hamma Hamma River and Skokomish River. The mountain's name honors Louis Forniquet Henderson (1853-1942), a pioneering botanist and mountaineer who accompanied Lieutenant O'Neil on his 1890 expedition into the Olympic Mountains.