The upper river then passes through Heiden Canyon before meeting and paralleling the Richardson Highway.
Following this, it enters the narrow and steeply walled Keystone Canyon, which marks the transition between the upper and lower river.
The lower river exits the canyon and turns northwest into a broad valley approximately 10 miles in length.
It was named by William R. Abercrombie in honor of Lt. Perceval Lowe, a member of an exploratory mission in the area led by Abercrombie.
This article related to a river in Alaska is a stub.