Prior to 1859, there were three crossings of the South Platte.
“These were commonly known as the Lower, Middle, and Upper crossings (or fords). Their respective locations would be roughly (1) a few miles west of the city of North Platte, in the vicinity of Fremont Springs, opposite Hershey, (2) a few miles east of Ogalala, and (3) a few miles west of Brule, Nebraska.
The one most heavily used was the Upper Crossing, otherwise variously known as Kearney’s Ford (from the 1845 expedition), Beauvais’ Crossing (from the nearby trading post), Laramie Crossing, Ash Hollow Crossing, or California Crossing. After 1859, with a new California Crossing at Julesburg, this became the Old California Crossing. (The terms Lower California Crossing and Upper California Crossing used by some latter-day historians to differentiate between the Ash Hollow Crossing and the Julesburg Crossing are nowhere to be found in emigrant journals and have resulted only in confusion. Frank Root seems to have invented this usage in his reminiscences.”