All - Architectural style - Italianate architecture
| Sessions House |
| Seul Choix Pointe Light Station |
| Seven Star Grange, No. 73 |
| Seward House |
| Sharp, Morris, House |
| Shattuck, Ralph W., House |
| Shay's Warehouse and Stable |
| Sheeley House |
| Shelley-Tipton House |
| Shriner-Ketcham House |
| Siebels' Department Store-Boyer Valley Bank |
| Simerly-Butler House |
| Skillman House |
| Skinner, Richard M., House |
| Sloan, Samuel, House |
| Smith, Adam and Mary, House |
| Smith, Adon, House |
| Smith, Alvord I., House |
| Smith, Benjamin, House |
| Smith County Jail, 1881 |
| Smith Farmhouse |
| Smith, Francis West, House |
| Smith, George W., Homestead |
| Smith, Henry W., House |
| Smith, John, House |
| Smith-Joseph-Stratton House |
| Smith, Perez, House |
| Smith, Peter and Mary, House |
| Smith, Samuel G., Farm |
| Smith, Turner and Amelia, House |
| Smith-Turner House |
| Snowden House |
| Sonoma Plaza |
| Southall Drugs |
| South School |
| Southworth House |
| Southworth House |
| Spalding County Courthouse-Spalding County Jail |
| Spensley Farm |
| Sperry-Smith House |
| Stadtmuller House |
| Stafford House |
| Stanley, Leonard W., House |
| Stansbury House |
| Star Theatre |
| Station and General Office, California Southern Railroad |
| St. Cecilia School |
| St. Charles City Bakery |
| St. Charles-Muller's Hotel |
| Stearns Iron-Front Building |
| Stearns-Wadsworth House |
| Steckart and Falck Double Block |
| Stedman & Fuller Manufacturing Company Complex |
| Stedman, Sarah Lowe, House |
| Steele, John, House |
| Stein, Daniel, House |
| Stein, Frederick W., House |
| Stevens-Buchanan House |
| Steven's, Dr., House |
| Stewart, A. T., Company Store |
| Stickney, George, House |
| Stimpson, Forrest J., House |
| St. John's Church Historic District |
| St. Joseph's Academy |
| St. Luke's Hospital |
| Stockbrands and Kemmerer Department Store |
| Stone, Capt. Nataniel, House |
| Stone Manor |
| Stoner, Joseph J., House |
| St. Patrick Catholic Church and Rectory |
| St. Paul's Methodist Church |
| Street, John, House |
| Strivers' Section Historic District |
| Sts. Peter & Paul Church and Rectory |
| Stuckslager, Harrison, House |
| Sturdivant-Sawyer House |
| Sturm, Louis H., Hardware Store |
| Sudley Place |
| Sunnyhill Home |
| Sunny Side |
| Swadkins, Thomas, House |
| Swetland House |
| Sycamore-13th Street Grouping |
| Tallman House |
| Tama County Jail |
| Tangeman, John, House |
| Tanglewood |
| Tanner, William A., House |
| Tappan-Viles House |
| Tauy Jones Hall |
| Taylor, David, House |
| Taylor, Lucy Hobbs, Building |
| Taylor, Moses J., House |
| Taylor, Oscar, House |
| Taylor, Wenzil, Building |
| Tedford, W. H., House |
| Tenement Building at 97 Orchard Street |
| Tevis, D. W. B. and Julia Waddell, House |
| Thaxter, Celia, House |
| Thayer, H. Elmer, House |
Data from United States Park Service and Wikidata
