Pennsylvania - Criteria: C (architecture/engineering)
| Morton, Morton, House |
| Moselem Farms Mill |
| Most Precious Blood Roman Catholic Church, Rectory and Parochial School |
| Mother Bethel A.M.E. Church |
| Mountain Meadow Farm |
| Mountain Springs Hotel |
| Mount Airy Historic District |
| Mount Hope Estate |
| Mount Joy |
| Mount Pleasant |
| Mount Pleasant Armory |
| Mount Pleasant Historic District |
| Mount Pleasant Historic District |
| Mount St. Peter Roman Catholic Church |
| Mount Union Historic District |
| Mount Vernon Furnace |
| Moxham Historic District |
| Moyer, John Nicholas and Elizabeth, House |
| Mt. Airy Station |
| Mt. Pleasant Iron Works House |
| Muddy Creek Bridge, Maryland and Pennsylvania Railroad |
| Muddy Creek Forks Historic District |
| Muhlenberg, Henry Melchoir, House |
| Muhlenberg School |
| Muhr, Simon, Work Training School |
| Mulford Building |
| Mulford, Sylvanus, House |
| Mumma, Samuel N., Tobacco Warehouse |
| Munce, Thomas, House |
| Muncy Historic District |
| Municipal Building and Central Fire Station, 340 |
| Murray, Thomas, House |
| Nace (Neas), George, House |
| Narbrook Park Historic District |
| Nathan's Department Store |
| National Bank of Coatesville Building |
| National Bank of North Philadelphia |
| National Transit Building |
| Nazareth Historic District |
| Nearpass House |
| Nebinger, George W., School |
| Neff, Maj. John, Homestead |
| Neff Round Barn |
| Neff's Mill Covered Bridge |
| Neill-Mauran House |
| Nelson, John H., House |
| Nesquehoning High School |
| Neuweiler Brewery |
| New Baltimore Bridge |
| New Berlin Presbyterian Church |
| New Castle Armory |
| New Century Clubhouse |
| New Colonial Hotel |
| New Era Building |
| New Freedom Railroad Station, Northern Central Railway |
| New Geneva Historic District |
| New Hope Village District |
| New Kensington Downtown Historic District |
| New Kensington Production Works Historic District |
| Newlin Mill Complex |
| Newlin Miller's House |
| Newlin, Nicholas, House |
| Newmyer, Peter and Jonathan, Farm |
| Newport Historic District |
| New Ringgold Gristmill |
| Newtown Creek Bridge |
| Newtown Friends Meetinghouse and Cemetery |
| Newtown Historic District |
| Newtown Presbyterian Church |
| Newville Historic District |
| New York Mutual Life Insurance Company Building |
| Nicholas, Jacob, House |
| Nichols, Jeremiah, School |
| Ninth Street Bridge |
| Nissly-Stauffer Tobacco Warehouses |
| Nissly Swiss Chocolate Company |
| Nitre Hall |
| Noble, J. L. School |
| Nook, The |
| Noon, Philip, House |
| North Broad Street Mansion District |
| North Broad Street Station, Reading Company |
| North Charlotte Street Historic District |
| North East Historic District |
| Northeast Lancaster Township Historic District |
| Northeast Manual Training School |
| Northern Liberties Historic District |
| Northern National Bank |
| Northern Saving Fund and Safe Deposit Company |
| North Hill Historic District |
| North Prince Street Historic District |
| North Scranton Junior High School |
| Northumberland County Courthouse |
| Northumberland Historic District |
| North Warwick Historic and Archeological District |
| North Wayne Historic District |
| Northwest York Historic District |
| N. Shippen-Tobacco Avenue Historic District |
| Nugent Home for Baptists |
| Nutt, Adam Clarke, Mansion |
Data from United States Park Service and Wikidata
