1935 Map of Irwin

About this map

The Snake River carves a deep valley through the Teton National Forest in this mid-1930s survey of the Idaho-Wyoming border. Small settlements like Irwin and Swan Valley anchor the riverfront, while the Caribou Range rises to the south, home to the high-elevation mining site of Caribou City. The landscape is a network of forest service infrastructure and rural school districts, including the Fidelity and Blowout schools. To the southwest, the expansive Gray's Lake dominates the high plateau, managed by the Grays Lake Ranger Station. Before modern damming altered the local hydrology, transit relied on crossings like Edwards Ferry, and the economy was supported by sites like Weeks Sawmill near Baldy Mountain. The map also captures the Boise Base Line as it intersects this complex terrain of ridges and basins.