1955 Map of Lukachukai

In the southern reaches of the quadrangle, the high plateau gives way to the deep, complex drainages of Canyon De Chelly National Monument. Water management for the area is marked by the Tsaile Reservoir and the winding course of Tsaile Creek. This survey was conducted in cooperation with the Atomic Energy Commission, reflecting the strategic importance of the Four Corners region during the Cold War era, while recording traditional sites such as the St Ann Church and various unnamed ruins scattered through the canyons.