[2] Portal Peak is located immediately northwest of Red Pass, and 1.36 mi (2.19 km) west-northwest of line parent White Mountain.

Topographic relief is significant as the summit rises 4,000 feet (1,219 meters) above the North Fork Sauk River in 1.5 miles (2.4 km).

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

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 North Cascades area.