Maryland - Criteria: C (architecture/engineering)
| Scott, Lula G., Community Center |
| Scott, Robert and Phyllis, House |
| Scott, Upton, House |
| Search Well |
| Sellers Mansion |
| Senator Theatre |
| Seneca Quarry |
| Seton Hill Historic District |
| Seven-Foot Knoll Lighthouse |
| Shaarei Tfiloh Synagogue |
| Shafer's Mill |
| Shaffer, Jacob F., Farm |
| Sharpsburg Historic District |
| Sharp Street Memorial United Methodist Church and Community House |
| Shaw Mansion |
| Sheffer, Daniel, Farm |
| Shepherd's Delight |
| Sheppard and Enoch Pratt Hospital and Gatehouse |
| Sherwood Manor |
| Shoemaker, Henry, Farmhouse |
| Shot Tower |
| Shrewsbury Church |
| SILVER HEEL (log canoe) |
| Silver Houses Historic District |
| Silver Spring Baltimore and Ohio Railroad Station |
| Simpson's Grove |
| Sion Hill |
| Slagle-Byers House (CARR-821) |
| Slate Ridge School |
| Smeltzer, Henry, Farmstead |
| Smith, Gov. John Walter, House |
| Smith, William S., House |
| Snively Farm |
| Snow Hill |
| Sonneborn Building |
| Sophia's Dairy |
| Sotterley |
| South Chesapeake City Historic District |
| Southern District Police Station |
| Southern Terminal, Susquehanna and Tidewater Canal |
| South Prospect Street Historic District |
| South River Club |
| Spacecraft Magnetic Test Facility |
| Sprechers Mill House |
| Spring Bank |
| Springfield Presbyterian Church |
| Spring Hill Church |
| Spye Park |
| Stagg Hall |
| St. Alphonsus' Church, Rectory, Convent and Halle |
| Stancioff House |
| Standard Oil Building |
| St. Andrew's Church |
| St. Andrew's Episcopal Chapel |
| Stanton Center |
| Stanton's Mill |
| St. Bartholomew's Episcopal Church |
| St. Brigid's School and Convent |
| St. Charles College Historic District |
| St. Euphemia's School and Sisters' House |
| Stevensville Bank |
| Stevensville Historic District |
| Stewart's Department Store |
| St. Francis Xavier Church and Newtown Manor House |
| St. George's Parish Vestry House |
| St. George's Protestant Episcopal Church |
| St. Giles |
| St. Ignatius Church |
| Still Pond Historic District |
| St. James Church |
| St. James Church |
| St. James the Less Roman Catholic Church |
| St. John's Chapel of St. Michael's Parish |
| St. John's Church |
| 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. Joseph's College and Mother Seton Shrine |
| St. Leo's Church |
| St. Luke's Church |
| St. Luke's Church |
| St. Mark's Episcopal Church |
| St. Mark's Episcopal Church-Lappans |
| St. Martins Church |
| St. Mary's Benefical Society Hall |
| St. Mary's Church |
| St. Marys City Historic District |
| St. Mary's Episcopal Church/Woodlawn |
| St. Mary's Roman Catholic Church, Newport |
| St. Mary's Seminary Chapel |
| St. Matthew's Church |
| St. Michael's Church |
| St. Michaels Historic District |
| Stonebraker and Harbaugh-Shafer Building |
| Stone Hall |
| Stone Hill Historic District |
| Stoneleigh Historic District |
| Stoner-Saum Farm |
Data from United States Park Service and Wikidata
