1931 Map of Moon Mtn

About this map

The Colorado River serves as the primary boundary and lifeline in this early twentieth-century survey of the Arizona-California border. The landscape is dominated by the Dome Rock Mountains and the prominent Moon Mtn, which rise sharply above the La Posa Plain. Much of the western territory is designated as the Colorado River Indian Reservation, reflecting the administrative and social geography of the era. Evidence of mineral prospecting is visible in the southeastern reaches of the mountains, specifically at the Valenzuella Mine and Mammoth Mine. Drainage patterns like the Tyson Wash illustrate the seasonal hydrology of this arid region, providing a detailed look at the intersection of natural topography and mining history before mid-century developments.