 Since the slave trade was illegal, the traders kept neither records of their activities nor the extent of their travels and explorations.Travelers along the Old Spanish Trail gave Castle Valley its names, as the travelers marveled at the imposing rock formations.The first Americans to come to Castle Valley were fur trappers, including the "lost trappers", James Workman and William Spencer, who had been separated from their trapping party by Comanche Indians and had wandered all the way to the Moab crossing of the Colorado River hoping that they would find Santa Fe.