Yukon River- Upper Region
The Upper Yukon Region occupies 69,000 square miles in the west central part of the state. The crest of the Brooks Range forms the rugged boundary to the north, while the Hodzana Highlands and Yukon-Tanana Uplands form a rolling hill boundary to the south and west. The United States-Canada border marks the artificial eastern boundary along the 141st parallel. The Yukon River divides this region, flowing through canyons called the Upper Ramparts and Lower Ramparts, at the western and eastern extremes. At the center of this region lie the broad 40 by 150 mile, Yukon Flats, which consists of marshy, small lake dotted flatlands tilted toward the west.