Dumbell Mountain is an 8,416-foot (2,565-metre) double summit massif located in the Glacier Peak Wilderness of the North Cascades, in Chelan County of Washington state.

[3] Dumbell Mountain is located in the Cloudy Pass batholith, an intrusive formation that was formed approximately 20 million years ago, during the early Miocene.

[5] In addition, small fragments of the oceanic and continental lithosphere called terranes created the North Cascades about 50 million years ago.

[5] During the Pleistocene period dating back over two million years ago, glaciation advancing and retreating repeatedly scoured and shaped the landscape.

[3] Uplift and faulting in combination with glaciation have been the dominant processes which have created the tall peaks and deep valleys of the North Cascades area.