As I was driving north along Arizona Highway 75 paralleling Emory’s trail I happened to glance to my right and saw what appeared to be the well-preserved ruin of a large building on top of the terraces that bound the Gila River’s floodplain. The appearance of this object was so striking that I had to pull over and check it with binoculars to see if it was man-made. It turned out to be a squared-off layer of rock on top of the terrace.
Lieutenant Emory’s reaction was similar to mine. Here’s a portion of his journal entry for October 25, 1846:
We were now approaching the regions made famous in olden times by the fables of Friar Marcos, and eagerly did we ascend every mound, expecting to see in the distance what I fear is but the fabulous “Casa Montezuma.” Once, as we turned a sharp hill, the bold outline of a castle presented itself, with the tops of the walls horizontal, the corners vertical, and apparently one front bastioned. My companion agreed with me that we at last beheld this famed building; on we spurred our unwilling brutes; restless for the show, I drew out my telescope, when to my disappointment a clay butte, with regular horizontal seams, stood in the place of our castle; but to the naked eye the delusion was complete. It is not impossible that this very butte, which stands on an imposing height in the centre of a vast amphitheatre of turreted hills, has been taken by the trappers, willing to see, and more especially to report, marvelous things for the “Casa Montezuma.”
The “castle” is at GPS coordinates N32° 51′ 03″ W109° 08′ 58″. The picture spot and the castle are located on the USGS “Sheldon, AZ” 7.5′ Topo map.