| Split Rock | Wyoming State Historic Preservation Office |
| Spotted Tail, Brule Lakota chief | Tom Rea |
| Spring Creek Raid | John W. Davis |
| Spring Creek Raid Site | |
| Stagecoach and Mail Road, Rawlins to Fort Washakie | J. Tom Davis, Rebecca Hein |
| Stagecoach Museum | |
| Stagecoach, Casper-Thermopolis line, 1901 | J. Tom Davis |
| Star Valley Pioneer and History Museum | |
| Starkweather, Charles | Lesley Wischmann |
| State boundary monument for Utah, Idaho and Wyoming | |
| State Flag, Wyoming | Kylie Louise McCormick |
| State Prison, Wyoming’s First | Lori Van Pelt |
| Statehood: Constitutional Convention, Debates and Their Aftermath | Phil Roberts |
| Steamboat Exhibit, University of Wyoming | |
| Stegner, Wallace and South Pass preservation | Will Bagley |
| Stepp, Alonzo, black rancher in the Green River Valley | WyoHistory.org, Jonita Sommers |
| Stewardess training, Cheyenne | Michael Kassel, Starley Talbott |
| Stewart, Elinore Pruitt, Writer and Homesteader | Barbara Allen Bogart |
| Stimson, Joseph E., Wyoming photographer | Wyoming State Historic Preservation Office |
| Strausner, Adam LeRoy, oral history | Dana Van Burgh |
| Sublette County Public Library | |
| Sublette County, Wyoming | Ann Chambers Noble |
| Suggs, Wyoming | |
| Sullivan, Mike | Wyoming State Archives |
| Sullivan, Mike, U.S. ambassador to Ireland, oral history | Tom Rea |
| Swain, Louisa, first woman to vote under Wyoming Territory’s new woman suffrage law | Wyoming State Archives |
| Swan Land and Cattle Company | Rebecca Hein |
| Swan, Alexander | Rebecca Hein |
| Sweetwater County Historical Museum | |
| Sweetwater County, Wyoming | Dudley Gardner |
