The mountain's name is taken from the river's name, which was applied by Albert Hale Sylvester (1871-1944), a pioneer surveyor, explorer, topographer, and forest supervisor in the Cascades.

Geological events occurring many years ago created the diverse topography and drastic elevation changes over the Cascade Range leading to various climate differences.

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

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

[2] 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.