1940 Map of Iris Pass

About this map

The U S Naval Reservation (Chocolate Mountain Aerial Gunnery Range) dominates this 1940 aerial survey, reflecting the rapid militarization of the California desert on the eve of American involvement in World War II. The landscape is defined by the sharp rise of the Chocolate Mountains and the Chuckwalla Mts, separated by strategic gaps such as Iris Pass and Augustine Pass. While the northern reaches remain a focused military corridor, the southwest corner shows the critical infrastructure of the Imperial Valley irrigation system, featuring the Coachella Canal and the East Highline Canal. Historical transit routes like the Ehrenberg Augustine Pass Road and Niland Road trace through the arid terrain, connecting the high passes to the developing agricultural basins below. Landmarks like Lion Head Mtn and the ephemeral Arroyo Seco provide fixed points for navigating this formidable desert environment.