From the record
“El Camino del Diablo, also known as El Camino del Muerto, Sonora Trail, Sonoyta-Yuma Trail, Yuma-Caborca Trail, and Old Yuma Trail, is a historic 250-mile (400 km) road that passes through some of the most remote and inhospitable terrain of the Sonoran Desert in Pima County and Yuma County, Arizona. The name refers to the harsh, unforgiving conditions on the trail.”
Wikipedia article El Camino del Diablo, CC BY-SA 4.0.
One of 204 National Register listings published here for Pima County · listed in 1978 · category: Structure.
Sources: the Wikipedia article · the case file at the National Archives · the National Register database, National Park Service