Pennsylvania - Role: Building
| Marsh Creek Advent Church |
| Martin, B. B., Tobacco Warehouse |
| Martin, C.F. & Company. |
| Martin Farmstead |
| Martin, James, School |
| Martin-Little House |
| Martin Orthopedic School |
| Martin Tower |
| Mary B. Sharpe School |
| Mary Immaculate Seminary (MIS) |
| Mascot Roller Mills |
| Mask and Wig Club of the University of Pennsylvania |
| Masonic Temple |
| Masonic Temple |
| Masonic Temple and Scottish Rite Cathedral |
| Massey, Thomas, House |
| Matlack, Enoch, House |
| Mauer, Dr. Joseph House |
| Maxwell, Ebenezer, House |
| Mayer Building |
| Mayer, David M., House |
| Mayfair House |
| McAllister, Archibald, House |
| McAllister-Beaver House |
| McCallum Manor |
| McCleary Elementary School |
| McClelland Homestead |
| McClenathan, J.C., Dr., House and Office |
| McClintock Hall |
| McClure, Alexander K., School |
| McCollum and Post Silk Mill |
| McConnell House |
| McCook Family Estate |
| McCormick, John B., House |
| McCoy House |
| McCoy-Shoemaker Farm |
| McDaniel, Delaplaine, School |
| McDowell Memorial Presbyterian Church |
| McFarlane, Andrew and Jennie, House |
| McGovern, Edward, Tobacco Warehouse |
| McIlvain, Francis, House |
| McKeesport National Bank |
| Meade, George, School |
| Meason, Isaac, House |
| Mechanicsville School |
| Mecky, A., Company Building |
| Media Armory |
| Meehan, Thomas, School |
| Meier, Isaac, Homestead |
| Melchinger, Englehart, House |
| Melester Barn |
| Melrose |
| Memorial Church of Our Father |
| Memorial Hall |
| Memorial Presbyterian Church |
| Mennonite Meetinghouse |
| Mentzer Building |
| Mercer County Court House |
| Mercer Museum |
| Merchants Cigar Box Company |
| Merchants' Exchange Building |
| Meredith, Daniel, House |
| Meredith, Simon, House |
| Meredith, Stephen, House |
| Meredith, William M., School |
| Merion Cricket Club |
| Merion Friends Meeting House |
| Merit Underwear Company |
| Merkel Mill |
| Merkel Mill Complex |
| Merrick Art Gallery |
| Methodist Episcopal Church of Burlington |
| Metropolitan Opera House |
| Metz Ice Plant |
| Meyerhoff, Son and Company Building |
| Michael, John, Farm |
| Michener, Nathan, House |
| Middishade Clothing Factory |
| Middlekauff, Jacob and Juliana, House |
| Mifflin County Courthouse |
| Mifflin Elementary School |
| Mifflin School |
| Mifflin, Thomas, School |
| Miles-Humes House |
| Mill at Lobachsville |
| Miller, Andrew S. and Elizabeth, House |
| Miller, Christian, House |
| Miller, David H., Tobacco Warehouse |
| Miller Hall |
| Miller, James, House |
| Millersburg Passenger Rail Station |
| Miller's House at Spring Mill |
| Miller's Store |
| Milleysack, J. B. Cigar Factory |
| Mill Grove |
| Millmont Farm |
| Mill-Rae |
| Mill Rift Hall |
| Mill Tract Farm |
| Milmoral |
Data from United States Park Service and Wikidata
