Maryland - Criteria: C (architecture/engineering)
| St. Paul's by-the-sea Protestant Episcopal Church |
| St. Paul's Cemetery |
| St. Paul's Chapel |
| St. Paul's Church |
| St. Paul's Church Rectory |
| St. Paul's Episcopal Church |
| St. Paul's Episcopal Church |
| St. Paul's Methodist Episcopal Church |
| St. Paul's Parish Church |
| St. Paul's Protestant Episcopal Church |
| St. Paul's Protestant Episcopal Church |
| St. Peter's 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' Church |
| St. Thomas Manor |
| St. Vincent De Paul Roman Catholic Church |
| Sudbrook Park |
| Sudler's Conclusion |
| Sudley |
| Summer Hill |
| Summit |
| Sumner, Charles, Post #25, Grand Army of the Republic |
| Sunnyfields |
| Sunnyside |
| Susanna Farm |
| Swansbury |
| Swiss Steam Laundry Building |
| Sycamore Cottage |
| Sydenham Hospital for Communicable Diseases |
| Sykesville Historic District |
| Takoma Avenue Historic District |
| Takoma Park Historic District |
| Tammany |
| Taney Place |
| Taneytown Historic District |
| Tawes, Capt. Leonard, House |
| Taylor, David W., Model Basin |
| Taylor-Manning-Leppo House |
| Taylor's Chapel |
| Teackle Mansion |
| Temora |
| TENNISON, WM. B. (Chesapeake Bay Bugeye) |
| Terminal Warehouse |
| Terra Rubra |
| Thainston |
| The Wilderness |
| Third Addition to Rockville and Old St. Mary's Church and Cemetery |
| Thomas House |
| Thomas Point Shoals Light Station |
| Thomas Run Church |
| Thomas Viaduct, Baltimore & Ohio Railroad |
| Thornton |
| Tidewater Inn |
| Timber Neck Farm |
| Tipahato |
| Tivoli |
| Todd Farmhouse |
| Tome School for Boys Historic District |
| Town Clock Church |
| Towson Academy |
| Traband, John H., House |
| Tracy's Landing Tobacco House No. 2 |
| Trevanion |
| Trinity Church |
| Troth's Fortune |
| Troy |
| Truman's Place |
| Trumpington |
| Truog, George, House |
| Tudor Hall |
| Tudor Hall |
| Tudor Hall |
| Tulip Hill |
| Tull, William T., House |
| Turkey Hill |
| Turkey Point Light Station |
| Turner-White Casket Co. Building |
| Tuscany-Canterbury Historic District |
| Twin Oaks |
| Tyrconnell |
| U-1105 BLACK Panther (Type VIIC German Submarine) |
| Union Baptist Church |
| Union Bridge Historic District |
| Union Bridge Station |
| Union Chapel |
| Union Mills Homestead Historic District |
| Union Square-Hollins Market Historic District |
| Union Station, WI-150 |
| Uniontown Academy |
| Uniontown Historic District |
| United States Parcel Post Station |
| University of Maryland Eastern Shore |
| Upper Fairmount Historic District |
Data from United States Park Service and Wikidata
