Canyon Diablo was a major obstacle to the explorers on the 35th parallel. It is virtually impassable by wagons, requiring a long detour to the north. At the point where it joins the Little Colorado River, however, the canyon disappears entirely. This area, near the Navajo community of Leupp, is where the Beale road crew crossed and then continued the road west.
An excerpt from Beale’s report:
September 8 , Camp 9. ..Travelling down the [Little Colorado] river bottom, which is here a wide valley on both sides, we came, in ten miles from the previous camp, to the mouth of the Canyon Diablo, where we encamped. This point is well marked by four little red sandstone buttes, which rise from the meadow near its mouth, and cannot be mistaken, as they are of peculiar form and isolated in position. They are about thirty or forty feet in height. We are now gaining on San Francisco mountain, which looks down on us this evening, and tomorrow we cross to encamp near its base.