Dumbell Mountain is an double summit massif located in the Glacier Peak Wilderness of the North Cascades, in Chelan County of Washington state. The Dumbell summit is slightly higher than the northeast subpeak (8,415 ft) which is unofficially called Greenwood Mountain. Its nearest higher neighbor is Chiwawa Mountain, to the east-southeast. Precipitation runoff from Dumbell Mountain drains into tributaries of the Chelan River and the Wenatchee River. The mountain's descriptive name was applied by Albert Hale Sylvester (1871-1944), a pioneer surveyor, explorer, topographer, and forest supervisor in the Cascades.