Maryland - Significance region: Local
| Slate Ridge School |
| Smeltzer, Henry, Farmstead |
| Smith, Gov. John Walter, House |
| Smith, Harry, House |
| Smith, William S., House |
| Snively Farm |
| Sonneborn Building |
| South Central Avenue Historic District |
| Southern District Police Station |
| Spring Bank |
| Springfield Presbyterian Church |
| Spring Hill Church |
| Spye Park |
| Stagg Hall |
| Stancioff House |
| Standard Oil Building |
| Stanton Center |
| Stanton's Mill |
| Starr Church |
| St. Bartholomew's Episcopal Church |
| St. Brigid's School and Convent |
| St. Charles College Historic District |
| St. Dennis Roman Catholic Church Complex |
| St. Elizabeth of Hungary |
| St. Euphemia's School and Sisters' House |
| Stevensville Bank |
| Stevensville Historic District |
| Stewart's Department Store |
| St. Giles |
| Stieff Silver Company Factory |
| Still Pond Historic District |
| St. James the Less Roman Catholic Church |
| St. John's Chapel of St. Michael's Parish |
| St. John's Church |
| St. John's Church at Creagerstown Historic District |
| St. John's Methodist Episcopal Church and Joshua Thomas Chapel |
| St. John's Protestant Episcopal Church |
| St. John the Evangelist Roman Catholic Church |
| St. Leo's Church |
| St. Mark's Episcopal Church |
| St. Mark's Episcopal Church-Lappans |
| St. Mary's Benefical Society Hall |
| St. Mary's Episcopal Church/Woodlawn |
| St. Mary's Roman Catholic Church, Newport |
| St. Michael's Church Complex |
| St. Michaels Historic District |
| Stonebraker and Harbaugh-Shafer Building |
| Stone Hill Historic District |
| Stoneleigh Historic District |
| Stoner-Saum Farm |
| St. Paul's by-the-sea Protestant Episcopal Church |
| St. Paul's Cemetery |
| St. Paul's Chapel |
| St. Paul's Episcopal Church |
| St. Paul's Episcopal Church |
| St. Paul's Methodist Episcopal Church |
| St. Peter's Methodist Episcopal Church |
| St. Peter the Apostle Church and Buildings |
| Stratton |
| Strawberry Hill |
| Streett, Col. John, House |
| St. Richard's Manor |
| St. Stephen's Episcopal Church |
| St. Thomas' Church |
| St. Thomas' Episcopal Parish Historic District |
| Sudler's Conclusion |
| Summer Hill |
| Sunnyfields |
| Sunnyside |
| Susanna Farm |
| Swansbury |
| Swiss Steam Laundry Building |
| Sycamore Cottage |
| Sydenham Hospital for Communicable Diseases |
| Sykesville Historic District |
| Takoma Avenue Historic District |
| Tammany |
| Taneytown Historic District |
| Tawes, Capt. Leonard, House |
| Taylor-Manning-Leppo House |
| Taylor's Chapel |
| Terminal Warehouse |
| Thainston |
| The Wilderness |
| Third Addition to Rockville and Old St. Mary's Church and Cemetery |
| Thomas and Company Cannery |
| Thomas Point Shoals Light Station |
| Thornton |
| Tidewater Inn |
| Timber Neck Farm |
| Tipahato |
| Tivoli |
| Todd Farmhouse |
| Tolson's Chapel |
| Town Clock Church |
| Traband, John H., House |
| Tracy's Landing Tobacco House No. 2 |
| Trinity Church |
| Trovinger Mill |
| Troy |
Data from United States Park Service and Wikidata
