Pennsylvania - Criteria: C (architecture/engineering)
| McGovern, Edward, Tobacco Warehouse |
| McIlvain, Francis, House |
| McKeesport National Bank |
| McKees Rocks Bridge |
| Meade, George, School |
| Meadville Downtown Historic District |
| Meason, Isaac, House |
| Mechanicsburg Commercial Historic District |
| Mechanicsville School |
| Mechanicsville Village Historic District |
| Media Armory |
| Meehan, Thomas, School |
| Meinig Glove Factory-Meinig, E. Richard, Co. |
| Melchinger, Englehart, House |
| Memorial Fountain and Statue |
| Memorial Hall |
| Mentzer Building |
| Mercer County Court House |
| Mercer Museum |
| Mercersburg Academy |
| Mercer's Mill Covered Bridge |
| Merchants' Exchange Building |
| Meredith, Daniel, House |
| Meredith, Simon, House |
| Meredith, Stephen, House |
| Meredith, William M., School |
| Merion Friends Meeting House |
| Merion Golf Club, East and West Courses |
| Merit Underwear Company |
| Merkel Mill |
| Merkel Mill Complex |
| Merrick Art Gallery |
| Merrill Lock No. 6 |
| Methodist Episcopal Church of Burlington |
| Metropolitan Edison Building |
| Meyers, Albertus L., Bridge |
| Michael, John, Farm |
| Michener, Nathan, House |
| Middishade Clothing Factory |
| Middlekauff, Jacob and Juliana, House |
| Middle Pickering Rural Historic District |
| Midtown Harrisburg Historic District |
| Mifflinburg Historic District |
| Mifflin County Courthouse |
| Mifflin Elementary School |
| Mifflin School |
| Mifflin, Thomas, School |
| Milanville Historic District |
| Miles-Humes House |
| Milford Historic District |
| Millanville-Skinners Falls Bridge |
| Mill at Lobachsville |
| Mill Creek Historic District |
| Miller, Christian, House |
| Miller, David H., Tobacco Warehouse |
| Miller Hall |
| Miller, James, House |
| Miller, Longdon L., Covered Bridge |
| Millersburg Passenger Rail Station |
| Miller's House at Spring Mill |
| Miller's Store |
| Milleysack, J. B. Cigar Factory |
| Millheim Historic District |
| Millionaire's Row Historic District |
| Millmont Farm |
| Mill Tract Farm |
| Milmoral |
| Milton Armory |
| Milton Freight Station |
| Milton Historic District |
| Minersville Historic District |
| Mishler Theatre |
| Mitchell, James, House |
| Mitchell-Shook House |
| Mitchell, S. Weir, School |
| Mixsell, Jacob, House |
| Monastery, The |
| Monongahela Cemetery |
| Monroe County Courthouse |
| Monroe Tavern |
| Monterey Historic District |
| Monte Vista |
| Montgomery House |
| Montgomery Ward Building |
| Montgomery, William, House |
| Montrose Historic District |
| Moore, Capt. Thomas, House |
| Moore, Clarence B., House |
| Moore Hall |
| Moravian Pottery and Tile Works |
| Moravian Sun Inn |
| Moreland-Hoffstot House |
| Morgan, Edward, Log House |
| Morgantown Historic District |
| Morris, Anthony, House |
| Morris-Hair Tavern |
| Morrison, Andrew J., School |
| Morrow, John, Elementary School |
| Morse, Samuel F. B., School |
| Morton Homestead |
Data from United States Park Service and Wikidata
