Big Chiwaukum is a prominent 8,098-foot (2,468-metre) mountain in Chelan County, Washington, United States.

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

Big Chiwaukum is composed of schist, part of the Nason terrane laid down 210 million years ago.

[6] During the Pleistocene period dating back over two million years ago, glaciation advancing and retreating repeatedly scoured the landscape leaving deposits of rock debris.

Uplift and faulting in combination with glaciation have been the dominant processes which have created the tall peaks and deep valleys of the Alpine Lakes Wilderness area.