Palo Duro Canyon (English)

Looking down Little Sunday Canyon past "The Lighthouse" (left) toward Palo Duro Canyon Prairie Dog Town Fork, one of the four principal sources of the Red River, rises at the western edge of the Llano Estacado—"Staked Plain"—in eastern New Mexico, flows intermittently for a hundred miles to the eastern edge of the high and semiarid flatland, then falls into spectacular Palo Duro—"Hard Stick"—Canyon.

The Freeman-Custis expedition didn't get that far upstream, of course, but the canyon may have been visited as early as 1541 by explorer Francisco Vásquez de Coronado.