Delaware - Criteria: A (event)
| Middletown Academy |
| Middletown Historic District |
| Milford New Century Club |
| Milford Railroad Station |
| Milford Shipyard Area Historic District |
| Mill Creek Friends Meetinghouse |
| Milton Historic District |
| Misty Vale |
| Mondamon Farm |
| Montchanin Historic District |
| Monterey |
| Moore Potato House |
| Morgan, William, Farm |
| Mount Cuba Historic District |
| Mount Lebanon Methodist Episcopal Church |
| Mount Pleasant |
| Naaman's Creek School |
| National Harbor of Refuge and Delaware Breakwater Harbor Historic District |
| Newark Passenger Station |
| New Castle and Frenchtown Railroad Right-of-Way |
| New Castle County Court House |
| New Castle Historic District |
| New Castle Ice Piers |
| New Castle Leather Raw Stock Warehouse |
| New Century Club |
| Newport National Bank |
| Newport Railroad Station |
| North Milford Historic District |
| North Saint Georges Historic District |
| Norwood House |
| Noxontown |
| Octagonal Schoolhouse |
| Odessa Historic District |
| Okolona |
| Old Asbury Methodist Church |
| Old Brick Store |
| Old Bridgeville Fire House |
| Old Cann Mansion House |
| Old College Historic District |
| Old Fire House |
| Old First Presbyterian Church of Wilmington |
| Old Fort Church |
| Old Newark Comprehensive School |
| Old St. Anne's Church |
| Old Statehouse |
| Old St. Paul's Methodist Episcopal Church |
| Old Sussex County Courthouse |
| Old Town Hall |
| Ott's Chapel |
| Owl's Nest Country Place |
| Pagan Creek Dike |
| Palmer Home |
| Penn Farm of the Trustees of the New Castle Common |
| Pepper, Carlton, David, Farm |
| Peterson and Mustard's Hermitage Farm |
| Philips-Thompson Buildings |
| Phillips Potato House |
| Phillips, Thomas, Mill Complex |
| Pierson, T., Farm |
| Pine Grove Furnace Site |
| Point Farm |
| Poplar Hall |
| Port Mahon Lighthouse |
| Port Penn Historic District |
| Public School No. 111-C |
| Public School No. 19 |
| Public School No. 29 |
| Quaker Hill Historic District |
| Ralph Potato House |
| Raymond Neck Historic District |
| Reading, Philip, Tannery |
| Redden Forest Lodge, Forester's House, and Stable |
| Reed, Jehu, House |
| Reedy Island Range Rear Light |
| Retirement Farm |
| Rhodes Pharmacy |
| Richards Historic District |
| Richards Mansion |
| Rider Potato House |
| Riverdale |
| Riverview Cemetery Company of Wilmington, Delaware |
| Robinson House |
| Rockland Historic District |
| Rodney Square Historic District |
| Roosevelt Inlet Shipwreck |
| Rosedale |
| Ross Point School |
| Rumsey Farm |
| Savin-Wilson House |
| Seaford Station Complex |
| Shallcross, Sereck, House |
| Short's Landing Hotel Complex |
| Smyrna Historic District |
| South Milford Historic District |
| Spring Banke |
| Springer, Charles, Tavern |
| Springer-Cranston House |
| Springer Farm |
| Spring Garden |
| Stanley Potato House |
Data from United States Park Service and Wikidata
