2020 Map of Porphyry Reef

About this map

Flathead National Forest and Lewis & Clark National Forest meet along a complex high-altitude boundary defined by the crests of the Sawtooth Range. The Continental Divide National Scenic Trail winds through this wilderness, traversing critical transitions at Sun River Pass and skirting the edge of Porphyry Reef. The terrain is characterized by dramatic ridges like Washboard Reef and Wapiti Ridge, which channel drainage into the N Fork Sun River and the W Fork Teton. Small alpine openings such as McDonald Park and Round Park offer breaks in the dense forest cover near McDonald Cr. This survey illustrates the intricate intersection of Flathead, Teton, and Lewis and Clark counties, where the hydrological divide dictates both the political boundaries and the primary routes of passage, such as the Monroe Cr Cutoff.