Ohio - Criteria: C (architecture/engineering)
| Methodist Church, Old |
| Methodist Church Parsonage |
| Methodist Episcopal Church |
| Methodist Episcopal Church of Painesville, The |
| Methodist Parsonage, Old |
| Metropolitan Block |
| Meyer House |
| Meyers, Capt., House |
| Miami County Courthouse and Power Station |
| Miami-Erie Canal Site Historic District |
| Miami Street Grade School |
| Michaels Farm |
| Middleport Public Library |
| Middle Sandy Presbyterian Church |
| Milan Historic District |
| Miles, Enos, House |
| Miles Park Historic District |
| Mill Creek Park Suspension Bridge |
| Millen-Schmidt House |
| Miller-Bissell Farmstead |
| Miller Block |
| Miller, Charles A., House |
| Miller, Daniel, House |
| Miller, Daniel, House |
| Miller, Frederick A., House-Broad Gables |
| Miller, Harvey, Residence |
| Miller, J.F., House |
| Miller, John, House |
| Miller-Leuser Log House |
| Miller, Lewis, House |
| Miller, Thomas, House |
| Mill Hollow House, The |
| Milligan, Cuthbert, House |
| Mills' Row |
| Mill Worker House No. 1 |
| Mill Worker House No. 3 |
| Mill Worker House No. 4 |
| Mill Worker House No. 5 |
| Minch, Capt., House |
| Miner's Supply Store |
| Minster Elementary School |
| Mitchell, Charles, House |
| Mitchell, Randolph, House |
| Mitchell, Richard H., House |
| Mohrman-Jack-Evans House |
| Monitor House |
| Monnett Memorial M. E. Chapel |
| Monroe Bank |
| Monroe County Courthouse |
| Monroe School |
| Monroe Township Hall-Opera House |
| Monteith Hall |
| Montgomery County Courthouse |
| Mooney, William C., House |
| Moore, Charles H., House |
| Moore, Edward W. and Louise C., Estate |
| Moormann, Bernard H., House |
| Morehouse-Downes House |
| Moreland Theater Building |
| Morgan-Hueston House |
| Morgan Mansion |
| Morley, Lewis, House |
| Morris, C. E., House |
| Morris House |
| Morrison House |
| Morristown Historic District |
| Morrow County Courthouse And Jail |
| Morrow-Overman-Fairley House |
| Mosgrove, Dr. Adam, House |
| Mosher House |
| Most Pure Heart Of Mary Church |
| Mother of Sorrows Church |
| Mott Drug Store |
| Mound City Group National Monument |
| Mound House |
| Mount Adams Public School |
| Mountain House |
| Mount Auburn Historic District |
| Mount Liberty Tavern |
| Mount Oval |
| Mount Pleasant Historic District |
| Mount Union College District |
| Mount Victory Historic District |
| Mount Zion Presbyterian Church |
| Mt. Healthy Public School |
| Mt. Olive Road Covered Bridge |
| Mt. Tabor Church Building, Cemetery and Hitching Lot |
| Mueller Brewery |
| Mueller, Christ, House |
| Mull Covered Bridge |
| Mumma, Jacob H. W., House |
| Municipal Building |
| Murphy, Daniel, Log House |
| Murray Hill School |
| Muskingum County Courthouse And Jail |
| Muskingum River Navigation Historic District |
| Musser, Henry, House |
| Mutual Home & Savings Association Building |
| Myer House |
| Myers Block-Home Company Building |
Data from United States Park Service and Wikidata
