| Name | What | Region | Country | Lat | Long | Elev Ft. | Pop Est |
| Stagecoach Hills | city | Illinois | United States | 42.42083 | -88.98083 | 748 | 14996 |
| Stagecoach Junction | city | Illinois | United States | 39.21861 | -89.61417 | 646 | 4229 |
| Staley | city | Illinois | United States | 40.11306 | -88.3125 | 741 | 40093 |
| Stallings | city | Illinois | United States | 38.72472 | -90.06306 | 416 | 33661 |
| Standard | city | Illinois | United States | 41.25667 | -89.18083 | 702 | 5933 |
| Standard City | city | Illinois | United States | 39.35222 | -89.7875 | 649 | 854 |
| Stanford | city | Illinois | United States | 40.43472 | -89.21778 | 662 | 1203 |
| Staples Corner | city | Illinois | United States | 42.13917 | -88.02167 | 744 | 128822 |
| Star City | city | Illinois | United States | 39.13417 | -90.67361 | 492 | 1327 |
| Stark | city | Illinois | United States | 40.99556 | -89.74389 | 649 | 970 |
| Starks | city | Illinois | United States | 42.08833 | -88.45667 | 938 | 5180 |
| Starne | city | Illinois | United States | 39.82417 | -89.605 | 567 | 70389 |
| State Park Place | city | Illinois | United States | 38.65861 | -90.04722 | 419 | 50187 |
| State Road | city | Illinois | United States | 40.07611 | -87.95833 | 659 | 1429 |
| Stateway Gardens subdivision | city | Illinois | United States | 41.82972 | -87.62778 | 590 | 562172 |
| Staunton | city | Illinois | United States | 39.01222 | -89.79111 | 626 | 8172 |
| Stavanger | city | Illinois | United States | 41.39861 | -88.61389 | 688 | 2823 |
| Steel City | city | Illinois | United States | 37.99806 | -88.87917 | 403 | 6783 |
| Steele | city | Illinois | United States | 41.50583 | -87.96222 | 702 | 30195 |
| Steeleville | city | Illinois | United States | 38.00722 | -89.65833 | 400 | 4038 |
| Steelton | city | Illinois | United States | 40.00944 | -87.67889 | 679 | 7555 |
| Steger | city | Illinois | United States | 41.47 | -87.63639 | 708 | 91417 |
| Sterling | city | Illinois | United States | 41.78861 | -89.69611 | 649 | 28752 |
| Sterling Place | city | Illinois | United States | 38.62639 | -90.03972 | 475 | 41579 |
| Steward | city | Illinois | United States | 41.84778 | -89.02 | 820 | 2010 |
| Stewardson | city | Illinois | United States | 39.26306 | -88.62972 | 649 | 1025 |
| Stewardsville historical | city | Illinois | United States | 40.3075 | -90.58222 | 669 | 605 |
| Stewart Ridge subdivision | city | Illinois | United States | 41.67389 | -87.63361 | 606 | 330162 |
| Stickney | city | Illinois | United States | 41.82139 | -87.78278 | 603 | 316049 |
| Stillman Valley | city | Illinois | United States | 42.10722 | -89.17917 | 731 | 1846 |
| Stillwell | city | Illinois | United States | 40.21861 | -91.18278 | 649 | 827 |
| Stiritz | city | Illinois | United States | 37.83611 | -88.94833 | 406 | 15005 |
| Stockdale | city | Illinois | United States | 41.35111 | -88.4925 | 515 | 8065 |
| Stockland | city | Illinois | United States | 40.61444 | -87.59278 | 688 | 859 |
| Stockton | city | Illinois | United States | 42.34972 | -90.00667 | 1046 | 1201 |
| Stoehrs | city | Illinois | United States | 40.52306 | -89.69361 | 515 | 12318 |
| Stokes | city | Illinois | United States | 38.0175 | -88.27389 | 400 | 958 |
| Stolle | city | Illinois | United States | 38.54333 | -90.16972 | 501 | 84608 |
| Stolletown | city | Illinois | United States | 38.69333 | -89.44667 | 449 | 1957 |
| Stone Church | city | Illinois | United States | 38.35028 | -89.62528 | 452 | 1102 |
| Stone Fort | city | Illinois | United States | 37.62333 | -89.19667 | 577 | 2327 |
| Stone Park | city | Illinois | United States | 41.90556 | -87.88361 | 639 | 198346 |
| Stonefort | city | Illinois | United States | 37.61417 | -88.70806 | 400 | 1118 |
| Stoneyville | city | Illinois | United States | 41.30472 | -88.83639 | 597 | 17620 |
| Stonington | city | Illinois | United States | 39.64 | -89.19278 | 610 | 961 |
| Stony Island | city | Illinois | United States | 41.7225 | -87.575 | 583 | 276055 |
| Stony Island Heights subdivision | city | Illinois | United States | 41.72667 | -87.57972 | 583 | 276055 |
| Stoy | city | Illinois | United States | 38.9975 | -87.83306 | 498 | 3431 |
| Strasburg | city | Illinois | United States | 39.3525 | -88.61917 | 639 | 1032 |
| Stratford | city | Illinois | United States | 41.99694 | -89.49083 | 807 | 3264 |
| Stratton | city | Illinois | United States | 38.44556 | -88.71333 | 515 | 1291 |
| Straut | city | Illinois | United States | 39.44333 | -90.70583 | 698 | 622 |
| Strawn | city | Illinois | United States | 40.6525 | -88.39639 | 770 | 945 |
| Strawns Crossing | city | Illinois | United States | 39.78583 | -90.15083 | 623 | 1718 |
| Streadle | city | Illinois | United States | 39.85333 | -89.61444 | 557 | 37159 |
| Streamwood | city | Illinois | United States | 42.02556 | -88.17833 | 810 | 91227 |
| Streator | city | Illinois | United States | 41.12083 | -88.83528 | 600 | 15663 |
| Streeterville subdivision | city | Illinois | United States | 41.89333 | -87.62194 | 580 | 231580 |
| Stringtown | city | Illinois | United States | 38.825 | -87.98361 | 475 | 1187 |
| Stronghurst | city | Illinois | United States | 40.74694 | -90.90389 | 698 | 845 |
| Stubblefield | city | Illinois | United States | 38.84833 | -89.46639 | 541 | 1414 |
| Sturbridge Village | city | Illinois | United States | 42.35194 | -89.07389 | 705 | 50859 |
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