Illinois - Significance region: Local
| Silhan, Mr. Robert, House |
| Silversmith Building |
| Sinnissippi Site |
| Sixth, Seventh, and Tenth Street Stone Arch Bridges |
| Skelly Service Station |
| Skinner, Richard M., House |
| Slaten-LaMarsh House |
| Sleeth Site |
| Sloane, William and Jennette, House |
| Small-Towle House |
| Smith, A. Herr and E. E., Public Library |
| Smith-Duncan, House and Eastman Barn |
| Smith, Ephraim, House |
| Smith, J. P., Shoe Company Plant |
| Smith, Tina Weedon, Memorial Hall |
| Snite, John Taylor, House |
| Snowden, Elsworth, House |
| Soffel, Albert, House |
| Soldiers and Sailors Memorial Hall |
| Soldiers' Monument |
| Solon, Francis and Abbie, House |
| Somerset Hotel |
| Soulsby Service Station |
| South Charter Street Historic District |
| South Fulton Churchhouse |
| South Henderson Church and Cemetery |
| South Park Manor Historic District |
| South Shore Bungalow Historic District |
| South Side German Historic District |
| South Water Market |
| Spafford, Amos Catlin, House |
| Sparta Historic District |
| Spiegel Office Building |
| Spivey Building |
| Sprague's Super Service |
| Springdale Cemetery |
| Spring-Douglas Historic District |
| Spring Valley House-Sulfur Springs Hotel |
| Squires, Frederick, House |
| Standard Oil Gasoline Station |
| Standard Oil Gasoline Station |
| St. Anne's Episcopal Church |
| Stapleford-Hover-Whitney House |
| Starr Hotel |
| State Bank Building |
| State Savings Loan and Trust |
| Stauduhar House |
| St. Charles Hospital |
| St. Charles Municipal Building |
| Stearns-Wadsworth House |
| Stephenson, Benjamin, House |
| Sterling Masonic Temple |
| Steuben Club, The |
| Stevens House |
| Steward, Lewis, House |
| Stickney, George, House |
| St. James Catholic Church and Cemetery |
| St. James Episcopal Church |
| St. Johns Episcopal Church |
| St. Louis, Peoria and Northern Railroad Depot |
| St. Louis Street Historic District |
| St. Luke's Hospital Complex |
| St. Mary's Church |
| St. Mary's Church of Gilberts |
| St. Matthew Evangelical Lutheran School |
| St. Nicholas Hotel |
| Stolp Island Historic District |
| Stolp Woolen Mill Store |
| Stone Arch Bridge |
| Stone Arch Bridge |
| Stone Manor |
| Stone Quarry Bridge |
| Stoner Site |
| Stone Temple Baptist Church |
| Stony Island Trust and Savings Bank Building |
| Storkline Furniture Corporation Factory |
| Story-Camp Rowhouses |
| Stotlar, Ed. M., House |
| St. Paulus Evangelisch Lutherischen Gemeinde |
| Strand Hotel |
| Strauss, Jesse L., Estate |
| Strawbridge-Shepherd House |
| Strawn, Jeremiah, House |
| Streator Public Library |
| Streibich Blacksmith Shop |
| Strevell House |
| St. Thomas Catholic High School for Boys |
| Sullivan, Joseph P. O., House |
| Sunderlage Farm Smokehouse |
| Sutherland Hotel |
| Swannell, Charles E., House |
| Swedish American Telephone Company Building |
| Swedish Club of Chicago |
| Swift, Louis F., House |
| Taft Farmstead |
| Talman West Ridge Bungalow Historic District |
| Tampico Mounds |
| Tanner, William A., House |
| Taylor Apartments |
| Taylor, Oscar, House |
Data from United States Park Service and Wikidata
