| Simpson, Milward - interview | Wyoming State Archives |
| Simpson’s Hollow | WyoHistory.org |
| Sixth Crossing of the Sweetwater, Oregon Trail historic site | WyoHistory.org |
| Smith, Nels | Wyoming State Archives |
| Snodderly, Quintina, Oregon Trail Grave of | WyoHistory.org |
| Solier, C.H., Wyoming State Hospital superintendent | Rebecca Hein |
| Spence, Gerry | WyoHistory.org |
| Spence, Gerry - interview | Wyoming State Archives |
| Stepp, Alonzo, black rancher in the Green River Valley | Jonita Sommers, WyoHistory.org |
| Stewart, Elinore Pruitt, Writer and Homesteader | Barbara Allen Bogart |
