| Shoshone Irrigation District | |
| Shoshone Reservation, 1905 Land Cession Agreement | WyoHistory.org |
| Siberia, 2nd Lt. Paul Kendall’s service in, 1919-1920 | Douglas R. Cubbison |
| Sidon Canal Historic Marker/Prayer Rock | |
| Simpson, Milward | Wyoming State Archives |
| Simpson, Milward - interview | Wyoming State Archives |
| Simpson, Milward and the death penalty | Robin Everett |
| Simpson’s Hollow | WyoHistory.org |
| Simpson’s Hollow | |
| Site of the Wagon Box Fight | |
| Sixth Crossing of the Sweetwater, Oregon Trail historic site | WyoHistory.org |
| Skiing, history of on Casper Mountain | Rebecca A. Hunt, Ph.D. |
| Smith, Alfred E. | Rebecca Hein |
| Smith, Nels | Wyoming State Archives |
| Snodderly, Quintina, Oregon Trail Grave of | WyoHistory.org |
| Snow King ski area | |
| Snowy Range Scenic Byway | |
| Solier, C.H., Wyoming State Hospital superintendent | Rebecca Hein |
| Sommers Ranch | Stephanie Lowe |
| South Pass | Will Bagley |
| South Pass and its monuments | |
| South Pass City | |
| South Pass City | WyomingHeritage.org, Wyoming State Historic Preservation Office |
| South Pass Gold Rush | Will Bagley |
| South Pass Overlook | |
| South Pass, discovery | Will Bagley |
| South Pass, early missionaries | Will Bagley |
| South Pass, First Wagons | Will Bagley |
| Spanish Diggings | |
| Sparks, Kliss, Cokeville bombing survivor oral history | Wyoming State Archives |
| Spearfish Canyon | |
| Spence, Gerry | WyoHistory.org |
| Spence, Gerry - interview | Wyoming State Archives |
| Spirit Mountain Cave | |
| Spirit Mountain Cave | Phil Roberts |
| Split Rock | |
