Ohio - Criteria: C (architecture/engineering)
| Maria Stein Catholic Church and Rectory |
| Marion Catholic School |
| Marion Cemetery Receiving Vault |
| Marion County Courthouse |
| Marion Township School District No. 3 |
| Marion Township Sub-District #8 School |
| Market Square |
| Mark Road Bridge |
| Marks-Family House |
| Marlow Theatre |
| Marmon, Martin, House |
| Marquart-Mercer Farm |
| Marshall, David, House |
| Marshall, James E., House |
| Marsh, George H., Homestead and the Marsh Foundation School |
| Marsh, Joseph, House |
| Martin Block and Kibby Block |
| Martin, Brooke and Anna E. House |
| Marting Hotel |
| Martin House |
| Martin, Joseph, House |
| Martinsville Road Covered Bridge |
| Marvin Memorial Library |
| Mason, Frank H., House |
| Mason House |
| Masonic Temple |
| Masonic Temple |
| Masonic Temple |
| Masonic Temple |
| Masonic Temple |
| Masonic Temple Building |
| Masonic Temple Building |
| Mason, James, House |
| Mason, John Wesley, Gothic Cottage |
| Massillon Cemetery Building |
| Massillon Downtown Historic District |
| Mather, Flora Stone, College District |
| Mathews House |
| Mattoon-Woodrow House |
| Maumee Sidecut |
| Maumee Theater |
| May Company |
| May, David and Mary, House |
| Mayer, S. C., House |
| May Realty Building |
| McBean, Daniel, Farmstead |
| McCafferty Run Farmstead |
| McCafferty, William, Farmhouse |
| McCarthy-Blosser-Dillon Building |
| McClelland, Harry S., House |
| McColly Covered Bridge |
| McCorkle, Almon G., House |
| McCormick Manufacturing Company Building |
| McCracken-McFarland House |
| McCracken-Scott House |
| McCracken-Sells House |
| McCrea, Matthew, House |
| McCreary-Burnworth House |
| McCrory Building |
| McCune's Villa |
| McDannald Homestead |
| McDonald Farm |
| McFarland, James, House |
| McGraw House |
| McKay, Moses, House |
| McKee-Pumphrey House |
| McKenster-Groff House |
| McKever, Lewis, Farmhouse |
| McKinley Memorial |
| McKinley School |
| McKinley School |
| McKinley Terrace |
| McKisson, Robert, House |
| McKitrick, Dr., House |
| McKitrick, Dr., Office |
| McLain-Gillmer House |
| McMillan, Reuben, Free Library |
| McPherson Town Historic District |
| McWilliams, Matthew, House |
| Mead House |
| Mead-Zimmerman House |
| Mechanics Building and Loan Company |
| Mechanicsburg Baptist Church |
| Medical Centre Building |
| Medina County Courthouse |
| Medina Masonic Temple and Medina Theater |
| Meeker, Forrest, House and Farm |
| Meigs County Fairgrounds, Grandstand and Racetrack |
| Melbourne Flats |
| Melville-Milne, William Gordon, House |
| Memorial Hall |
| Memorial Hall |
| Mendon Town Hall |
| Mentor Village School |
| Mercer Log House |
| Merriman, Wells E., House |
| Merryman, Dr. James, House |
| Mertz, John, House |
| Merwin, George, House |
| Metcalf, Rev. Harlan, House |
Data from United States Park Service and Wikidata
