“It is all part and parcel of the unsatisfactory nomenclature of the trail that South Pass is by no means to the south.
The descriptive title was first used by trappers who had moved into the untimbered, Indian-infested prairies along the northern reaches of the Missouri River. In 1823 trouble with the Arikaras closed this route, and a picked group of William Ashley’s mountain men, desirous of reaching the new trapping fields of the Green River, set out to locate the strange, smooth gap through the Rocky Mountains of which they had heard from the Indians. It lay to the south, in the country of the Crows, and they spoke of it as the South or Southern Pass.Directions of a kind were obtained at a Crow village and, after wintering as best they could, the trappers left the headwaters of the Sweetwater River, moving west across the mountains.The country was oddly flat, but sometime in March 1824, they discovered to their joy that the creeks were flowing westward under their sheaths of ice, and knew that they had reached the Pacific watershed. From this date the pass was known and used by white men.
The crossing of the Rockies was not dreaded by the emigrants, who knew from their guidebooks that the grade was easy and the summit flat and unbroken. That there might be exigencies on a mountain top beyond the danger of falling off did not occur to travelers to whom an elevation of seven thousand feet was an unheard-of experience. It was with as few misgivings as the uncertainty of the trail ever permitted that the wagon trains ascended the valley of the Sweetwater on their way to the pass.”