Chilly Peak is a 7,970-foot summit in Washington’s Entiat Mountains, part of the North Cascades, standing in the Okanogan–Wenatchee National Forest south of Ice Lakes. On the east side of the Cascade crest, it lies in a somewhat drier setting than peaks farther west, but still receives heavy precipitation, especially winter snow, and can remain snow-covered into late spring and early fall. The mountain rises from terrain shaped by tectonic and volcanic forces over millions of years and by repeated glaciation in the last two million years, which carved the deep valleys and rugged relief around it. Its runoff drains east to Ice Creek and west to Rock Creek.