North Fork of the Koyukuk River
NPS Photograph Teri McMillan
The North Fork of the Koyukuk flows from the south flank on the Arctic Divide through broad, glacially carved valleys in the rugged Endicott Mountains of the Central Brooks Range. It passes between Boreal Mountain and Frigid Crags dubbed the "Gates to the Arctic" by Bob Marshall. The North Fork joins the Middle Fork and can be run all the way to Bettles Field.