1954 Map of Picacho

About this map

The Trigo Mountains define this rugged corridor of the lower Colorado River basin, where industrial history meets protected desert wetlands. In the mid-1950s, the landscape was primarily divided between the sprawling Yuma Test Station military grounds and the riverfront habitats of the Imperial National Wildlife Refuge. Traces of earlier hard-rock mining are evident throughout the northern mountains, marked by the Red Cloud Mine, Dives Mine, and several shafts near Black Rock Wash. Along the riverbanks, the small settlement of Picacho and the nearby Picacho Mill Ruins stand as evidence of the area's transition from a mining and milling center to a more remote outpost. The complex waterway of the Colorado River is punctuated by significant backwaters like Island Lake and Ferguson Lake, which serve as critical landmarks for both conservation and navigation in the Imperial County and Yuma County borderlands.