Montana - Significance region: Local
| Sacajawea-Miles Parks Historic District |
| Saco Mercantile |
| Sacred Heart Church |
| Sage Creek Ranger Station |
| Saint John the Baptist Catholic Church |
| Saint Mary of the Assumption |
| Sanders County Jail |
| Sandstone and Cobblestone Schools |
| Sargent, Charles C., House |
| Sauser-Mercord Building |
| Scandinavian Methodist Church |
| Scenic Bridge |
| Scherlie, Anna, Homestead Shack |
| Schroeder Hospital |
| Scott-Forhan House |
| Sedan School |
| Sharp, John, House |
| Sharp's, Jay, Store |
| Sheehan Boardinghouse |
| Shelby Town Hall |
| Sherman, Byron R., House |
| Sherwood Lodge |
| Shonkin Creek Bridge |
| Shore, Thomas and Beulah, House |
| Silver Bow Brewery Malt House |
| Silver City Cemetery |
| Silver Creek School |
| Silver King Ranch |
| Silverman, Morris, House |
| Simmonsen's House |
| Simons Block |
| Sims-Garfield Ranch |
| Slayton Mercantile Co. |
| Smith House |
| Smith, T. W., House |
| Snell, Walrond and Elizabeth, House |
| Snyder House |
| Southern Hotel |
| South Tracy Avenue Historic District |
| South Tracy-South Black Historic District |
| Spalding-Gunn House |
| Spanish Creek School |
| Spannring, John Otto, Family Farm |
| Sperry Chalets |
| Spieth and Krug Brewery |
| Spieth Houses |
| Springhill School |
| Square Butte Jail |
| Square Butte School |
| Stafford's Grocery |
| Stark House |
| Stark School |
| Stateler Memorial Methodist Church |
| St. Benedict's Catholic School |
| Stearns Hall |
| Sterling, Fred T., House |
| Stevens, Dominic, House |
| Stevensville Feed Mill |
| Stevensville Grade School-United Methodist Church |
| Stevensville Mercantile Company Oil Storage Building |
| Stillwater County Courthouse |
| St. James Episcopal Church and Parish House |
| St. James Episcopal Church and Rectory |
| St. Joseph Catholic Church |
| St. Joseph's Catholic Church |
| St. Joseph's Catholic Mission Church |
| St. Leo's Catholic Church |
| St. Mark's Episcopal Church |
| St. Mark's Episcopal Church |
| St. Mary Utility Area Historic District |
| Stockmen's Bank of Martinsdale |
| Stoltz House |
| Stone Hill Springs Prehistoric District |
| Story Motor Company |
| Stout, John, House |
| St. Paul’s Mission Church |
| St. Peter's Catholic Church |
| St. Philip's Episcopal Church |
| Strawberry Mine Historic District |
| St. Richard's Church |
| Studebaker Building |
| St. Wenceslaus Catholic Church |
| St. Xavier Mission Church and Rectory |
| Sullivan, James J., House |
| Sullivan Rooming House |
| Summers-Quast Farmstead |
| Summit Lodge |
| Sun Camp Fireguard Cabin |
| Suydam, Hester E., Boarding House |
| Swan Lake Rock House Historic District |
| Swan River Bridge |
| Swan River Community Hall |
| Swanson Boathouse |
| Swanson Homestead |
| Symes Hotel |
| Symmes Park Missile |
| Target Range Elementary School |
| Taylor, Ray E., House |
| Teton County Courthouse |
| Thayer House |
Data from United States Park Service and Wikidata
