The old road, known as the Sonora, Colorado River, or Southern Emigrant Trail and later as the Butterfield Overland Mail Route, traversed Box Canyon just east of here. On January 19, 1847, the Mormon Battalion under the command of Lieutenant Colonel Philip St. G. Cooke, using hand tools, hewed a passage through the rocky walls of the narrow gorge for their wagons and opened the first road into Southern California.

Citation from California Office of Historic Preservation