Some of the interesting geology from the Brooks Mountain Range, northeast Alaska... The Brooks Range is a mountain range that stretches from west to east across northern Alaska and into Canada's Yukon Territory, a total distance of about 1100 km (700 mi). The mountains are not especially high, topping out at over 2,700 m (9,000 ft). This mountain range forms the northern-most drainage divide in North America, separating streams flowing into the Arctic Ocean and the North Pacific. The range roughly delineates the summer position of the arctic front. ( arctic front—The semipermanent, semicontinuous front between the deep, cold arctic air and the shallower, basically less cold polar air of northern latitudes; generally comparable to the antarctic front of the Southern Hemisphere. ) It represents the northern extent of tree-line, with no trees (apart from some isolated Balsam Poplar stands) occurring north of the continental drainage divide. As one of the remotest and least-disturbed wildernesses of North America, the mountains are teeming with wildlife, including Dall sheep, grizzly bears, and caribou.