Indiana - Criteria: C (architecture/engineering)
| Martinsville Northside Historic District |
| Martinsville Sanitarium |
| Martinsville Vandalia Depot |
| Masonic Temple |
| Masonic Temple |
| Masonic Temple |
| Masonic Temple |
| Massachusetts |
| Massachusetts Avenue Commercial District |
| Matthews Stone Company Historic District |
| Mayfield, Leroy, House |
| Mayleeno |
| McAllister Bridge |
| McClain, John W., House |
| McClelland-Layne House |
| McColloch-Weatherhogg Double House |
| McCormack-Bowman House |
| McCormick, Charles, Building |
| McCormick's Creek State Park Entrance and Gatehouse |
| McCurdy Building (Sears, Roebuck and Company Building) |
| McCurdy Hotel |
| McDonald, James and Lucinda, House |
| McGill, Charles S. and Mary, House |
| McHaffie, Melville F., Farm |
| McJohnston Chapel and Cemetery |
| McKay |
| McKim Observatory, DePauw University |
| McKinley School |
| McNamee-Ford House |
| Mead Johnson River-Rail-Truck Terminal and Warehouse |
| Mecca Bridge |
| Medora Covered Bridge |
| Meeks Avenue Historic District |
| Meier, George Philip, House |
| Melcher Bridge |
| Melodeon Hall |
| Merchants National Bank and Annex |
| Meridian-Forest Historic District |
| Meridian Park Historic District |
| Merit-Tandy Farmstead |
| Merrifield-Cass House |
| Metamora Historic District |
| Meyer, Dr. John and Gerda, House |
| Meyer, Joseph Ernest, House |
| Miami County Courthouse |
| Michael, Enos, House |
| Michigan City Breakwater Light |
| Michigan City East Pierhead Light Tower and Elevated Walk |
| Michigan City Lighthouse |
| Michigan City Post Office |
| Middletown Bridge |
| Middletown Commercial Historic District |
| Milan Masonic Lodge No. 31 |
| Milford, Marshall M., House |
| Mill Creek Bridge |
| Millen-Chase-McCalla House |
| Millen House |
| Miller, Arthur, House |
| Miller Town Hall |
| Millikan, Lovel D., House |
| Minnetrista Boulevard Historic District |
| Mishawaka Carnegie Library |
| Mishawaka Fire Station No. 4 |
| Mishawaka Reservoir Caretaker's Residence |
| Mitchell Downtown Historic District |
| Mitchell, Joseph, House |
| Mock School |
| Moffett-Ralston House |
| Mohr, Louis, Block |
| Monon Commercial Historic District |
| Monon Park Dancing Pavillion |
| Monroe Carnegie Library |
| Monroe County Courthouse |
| Monroe Terrace Historic District |
| Mont Clair |
| Monteith, Mark L. and Harriet E., House |
| Montgomery County Jail and Sheriff's Residence |
| Montgomery, T. Harlan and Helen, House |
| Montgomery Ward Building |
| Monticello Carnegie Library |
| Montpelier Carnegie Library |
| Moore/Carlew Building |
| Moore's Hill United Methodist Church |
| Mooresville Commercial Historic District |
| Mooresville Friends Academy Building |
| Moore, Thomas, House |
| Moore-Youse-Maxon House |
| Morehous Residential Historic District |
| Morey House |
| Morey-Lampert House |
| Morgan County Courthouse |
| Morgan County Sheriff's House and Jail |
| Morgan House |
| Morgan-Skinner-Boyd Homestead |
| Morgantown Historic District |
| Morningside Historic District |
| Morris-Butler House |
| Morrison Block (M. O'Connor Grocery Wholesalers) |
| Morrison, Francis H., House |
| Morton, Oliver P., House |
Data from United States Park Service and Wikidata
