Whistler Mountain is a 7,790-foot summit in Washington’s North Cascades, in the Okanagan Range between Washington Pass and Rainy Pass, with the North Cascades Highway curving around its southern base. Linked by ridge to nearby Cutthroat Peak, it rises more than 3,000 feet above Bridge Creek and the highway in about a mile, giving it a notably steep profile. Runoff drains into Bridge Creek below. The mountain lies in a marine west coast climate shaped by moist Pacific weather, bringing heavy winter rain and snow, summer clearing, and frequent avalanche danger. Its rugged form reflects millions of years of tectonic activity, uplift, faulting, and repeated Pleistocene glaciation.