| Name | What | Region | Country | Lat | Long | Elev ft. | Pop est |
|---|---|---|---|---|---|---|---|
| Fort Saint Charles | city | Minnesota | United States | 49.36 | -94.98 | 1066 | |
| Fort Saint Michael (historical) | city | Alaska | United States | 57.30 | -135.37 | 1197 | |
| Fort Saint Phillip (historical) | city | Louisiana | United States | 29.36 | -89.46 | 13 | |
| Fort Saint Vrain (historical) | city | Colorado | United States | 40.28 | -104.85 | 5029 | |
| Fort Salonga | city | New York | United States | 40.91 | -73.30 | 49 | |
| Fort Scammel | city | Maine | United States | 43.65 | -70.21 | 0 | |
| Fort Scott | city | Kansas | United States | 37.84 | -94.71 | 830 | |
| Fort Scott | city | Ohio | United States | 39.27 | -84.66 | 830 | |
| Fort Screven | city | Georgia | United States | 32.02 | -80.84 | 0 | |
| Fort Sedgwick (historical) | city | Colorado | United States | 40.94 | -102.38 | 3572 | |
| Fort Selden | city | New Mexico | United States | 32.48 | -106.91 | 4189 | |
| Fort Seneca | city | Ohio | United States | 41.21 | -83.17 | 830 | |
| Fort Seward | city | California | United States | 40.22 | -123.64 | 400 | |
| Fort Seybert | city | West Virginia | United States | 38.69 | -79.19 | 1669 | |
| Fort Shaw | city | Montana | United States | 47.51 | -111.81 | 3599 | |
| Fort Shawnee | city | Ohio | United States | 40.69 | -84.14 | 853 | |
| Fort Smith | city | Arkansas | United States | 35.39 | -94.40 | 830 | |
| Fort Smith | city | Georgia | United States | 34.63 | -83.97 | 1706 | |
| Fort Smith | city | Montana | United States | 45.31 | -107.94 | 3349 | |
| Fort Spokane | city | Washington | United States | 47.90 | -118.31 | 1669 | |
| Fort Spring | city | Kentucky | United States | 38.04 | -84.63 | 898 | |
| Fort Spring | city | West Virginia | United States | 37.75 | -80.54 | 1952 | |
| Fort Spunky | city | Texas | United States | 32.33 | -97.65 | 830 | |
| Fort Standish | city | Massachusetts | United States | 42.00 | -70.63 | 0 | |
| Fort Stanton | city | New Mexico | United States | 33.50 | -105.52 | 6200 | |
| Fort Steele | city | Wyoming | United States | 41.78 | -106.95 | 6709 | |
| Fort Stevens | city | Oregon | United States | 46.20 | -123.96 | 3 | |
| Fort Stewart | city | Georgia | United States | 31.86 | -81.52 | 19 | |
| Fort Stockton | city | Texas | United States | 30.89 | -102.88 | 3349 | |
| Fort Stoddard | city | Alabama | United States | 31.10 | -87.98 | 19 | |
| Fort Sumner | city | New Mexico | United States | 34.47 | -104.25 | 4189 | |
| Fort Supply | city | Oklahoma | United States | 36.57 | -99.57 | 2004 |