1949 Map of Gypsum Gap

About this map

The Atomic Energy Commission appears prominently on this late 1940s survey of the San Miguel region, reflecting the era's burgeoning interest in radioactive minerals. The landscape is defined by the massive geological corridor of Big Gypsum Valley and the neighboring Disappointment Valley to the south. These troughs are separated by Long Ridge, which served as a focal point for extraction as evidenced by the Long Ridge Mines. The map documents a rugged extractive frontier where numerous small infrastructure improvements—including several Dams, a Ditch, and a Flume—were required to manage water for industrial use. Prospectors and researchers can trace the specific locations of the Bald Eagle Mines and Pitchfork Mines, illustrating the intensity of postwar mineral exploration in this remote corner of Colorado.