Ernest Oberholtzer is educating the reader about the impact of proposed dams. This could be the Backus-proposed dams in the mid-1920s. Dotted lines, ink on parchment, define the Rainy Lake Watershed and the international border. Rail lines are drawn and major lakes are noted. This could well be Oberholtzer's hand-work. Map goes from the western shore of Lake of the Woods to Fort William on the east. Rainer [sic] town name is spelled wrong.
This is a map of the Boundary Waters region, and shows great detail on lake and river names. Area north of the international boundary is called "Hunter's Island." The roads and railroads are marked, as well as trails, ranger stations and telephone lines. Additions to the Superior National Forest Proclamation Boundary are shown using a reddish cross hatching.