Maine - Criteria: A (event)
| Record, Judson, House |
| Red Brick School |
| Redington House |
| Redwood |
| Reed, G. W., Travellers Home |
| Reed, Robert, House |
| Reed School |
| Reverie Cove |
| Richmond Historic District |
| Richmond's Island Archeological Site |
| Rivercroft Farm |
| River Meetinghouse |
| Roak Block |
| Robertson Quarry Galamander |
| Robinson-Parsons Farm |
| Robyville Bridge |
| Rockland Breakwater |
| Rockland Breakwater Lighthouse |
| Rockland Railroad Station |
| Rockland Turntable and Engine House |
| Rockport Historic District |
| Rockport Historic Kiln Area |
| Rock Rest |
| Roosevelt School |
| Roosevelt School |
| Ropes End |
| Rose, Robert, Tavern |
| Rumford Falls Power Company Building |
| Rumford Public Library |
| Rural Hall |
| Saco Central Fire Station |
| Saco City Hall |
| Saco Historic District |
| Saddleback Ledge Light Station |
| Sail Loft |
| Saint Saviour's Episcopal Church and Rectory |
| Salem Town House (Former) |
| Sanford Mills Historic District |
| Sanford Town Hall (Former) |
| Sangerville Town Hall |
| Sargent, Daniel House |
| Savings Bank Block |
| Scarborough High School |
| Schlotterbeck and Foss Building |
| Schoodic Peninsula Historic District |
| Scribner Homestead |
| Sea Change |
| Searsport Historic District |
| Seawall Campground |
| Sedgwick Historic District |
| Seguin Island Light Station |
| Seven Star Grange, No. 73 |
| Shaker Village |
| Sheepscot Historic District |
| Shiloh Temple |
| Shore Acres |
| Skowhegan Free Public Library |
| Skowhegan Historic District |
| Slate House |
| Smith, James, Homestead |
| Smith, Parson, House |
| Sodergren, John J. and Martha, Homestead |
| Soldiers Memorial Library |
| Somerset Academy |
| Somerset County Courthouse |
| Somesville Historic District |
| Songo Lock |
| Sorrento Library |
| Southard Block |
| South Berwick Village Historic District |
| South China Meeting House |
| South Street Historic District |
| Spring Point Ledge Light Station |
| Sproul Homestead |
| Sproul's Cafe |
| Spruce Point Camps |
| Sprucewold Lodge |
| Spurwink Congregational Church |
| Squirrel Point Light Station |
| Standish Corner Historic District |
| St. Andre's Parish |
| St. Anne's Church and Mission Site |
| Staples Inn |
| State Reform School Historic District |
| St. Croix Island International Historic Site |
| St. Cyril and St. Methodius Church |
| St. David Catholic Church |
| St. Denis Catholic Church |
| Stearns Hill Farm |
| Steep Falls Library |
| STEPHEN TABER (schooner) |
| St. Hyacinth School and Convent |
| Stimson Memorial Hall |
| St. John's Catholic Church |
| St. Joseph's Academy and Convent-Catherine McAuley School |
| St. Joseph's School |
| St. Lawrence Church |
| Stone Barn Farm |
| Stone House |
| Stone Schoolhouse |
Data from United States Park Service and Wikidata
