Maine - Criteria: C (architecture/engineering)
| Rockport Historic District |
| Roosevelt School |
| Roosevelt School |
| Ropes End |
| Rose, Robert, Tavern |
| Row House |
| Ruggles House |
| Rumford Falls Power Company Building |
| Rumford Point Congregational Church |
| Rumford Public Library |
| Ryefield Bridge |
| Saco City Hall |
| Saco High School (old) |
| Saco Historic District |
| Saddleback Ledge Light Station |
| Saint Jude's Episcopal Church |
| Saint Saviour's Episcopal Church and Rectory |
| Salmon Falls (East) Historic District |
| Salmon Falls (West) Historic District |
| Sanford Mills Historic District |
| Sangerville Town Hall |
| Sargent, Daniel House |
| Sargent, Levi, House |
| Sargent-Roberts House |
| Savings Bank Block |
| Scarborough High School |
| Schlotterbeck and Foss Building |
| Schoodic Peninsula Historic District |
| Scott, Capt. George, House |
| Scribner Homestead |
| Sea Change |
| Seal Harbor Congregational Church |
| Searsport Historic District |
| Seaverns, George, House |
| Seavey, A. B., House |
| Seavey-Robinson House |
| Seawall Campground |
| Second Callahan Block |
| Second Congregational Church |
| Security Trust Building |
| Sedgley, John, Homestead |
| Sedgwick Historic District |
| Sellers, Salome, House |
| Seton, Elizabeth Ann, Hospital |
| Sewell Memorial Congregational Church |
| Shaw, William M., House |
| Sheepscot Historic District |
| Skelton, Thomas, House |
| Skowhegan Fire Station |
| Skowhegan Free Public Library |
| Skowhegan Historic District |
| Slate House |
| Small Point Club |
| Smith-Emery House |
| Smith, F.O.J., Tomb |
| Smith, George W., Homestead |
| Smith, James, Homestead |
| Smith, Parson, House |
| Smith, Zebulon, House |
| Sodergren, John J. and Martha, Homestead |
| Soderholtz, Eric E., Cottage |
| Soldiers Memorial Library |
| Somerset Academy |
| Somesville Historic District |
| Songo Lock |
| Sorrento Library |
| Southard Block |
| South Berwick Village Historic District |
| South Bridgton Congregational Church |
| Southgate Farm |
| South Parish Congregational Church and Parish House |
| South Solon Meetinghouse |
| South Street Historic District |
| Sparrow House |
| Spaulding House |
| Spite House |
| Springdale Farm |
| Springfield Congregational Church |
| Spring Point Ledge Light Station |
| Spring Street Historic District |
| Sproul Homestead |
| Sprucewold Lodge |
| Squire Tarbox House |
| Squirrel Point Light Station |
| Standish Corner Historic District |
| St. Andre's Parish |
| St. Andrew's Church |
| St. Anne's Church and Mission Site |
| St. Anne's Episcopal Church |
| Star of Hope Lodge |
| State Reform School Historic District |
| St. David Catholic Church |
| Stearns Hill Farm |
| St. Edward's Convent, (Former) |
| Steep Falls Library |
| STEPHEN TABER (schooner) |
| Stetson Union Church |
| Stevens, John Calvin, House |
| Stewart Free Library |
| St. Hyacinth School and Convent |
Data from United States Park Service and Wikidata
