Indiana - Significance region: Local
| Linton Township High School and Community Building |
| Little Crow Milling Company Factory |
| Little Rock Creek Stone Arch Bridge |
| Lockefield Garden Apartments |
| Lockport Wabash River Bridge |
| Lockyear College |
| Lodge |
| Log Cabin Inn Tourist Camp |
| Lombard Building |
| Long Schoolhouse |
| Lords, William L., House |
| Loring, Dr. David J., Residence and Clinic |
| Lowell Commercial Historic District |
| Lowell Heights-Olivet African Methodist Episcopal Church |
| Lowry, William, House |
| Luckey Hospital |
| Luick, William Henry, Farmhouse |
| Lyles Consolidated School |
| Lynd School |
| Maack, Albert, House |
| Madden School |
| Madison County Bridge No. 149 |
| Maier, Peter Augustus, House |
| Majestic Building |
| Major, Daniel S., House |
| Makepeace, George, House |
| Mallon Building |
| Manche, Maurice W., Farmstead |
| Manchester Apartments |
| Mansfield Roller Mill |
| Mansion Row Historic District |
| Maple Grove Campground |
| Maple Grove Road Rural Historic District |
| Maplelawn Farmstead |
| Marble Creek Bridge |
| Marcy Village Apartments |
| Marian Apartments |
| Maring, Grace Keiser, Library |
| Marion Branch, National Home for Disabled Volunteer Soldiers Historic District |
| Marion Downtown Commercial Historic District |
| Marion Firestone Auto Supply & Service Center |
| Marion PCC & St. Louis Railroad Depot |
| Markle House and Mill Site |
| Marott Hotel |
| Marott's Shoes Building |
| Marquette School |
| Marr, James, House and Farm |
| Marshall County Court House |
| Marshall County Infirmary |
| Marshall, Thomas R., School |
| Mars Theatre |
| Martens |
| Martin County Courthouse |
| Martin Place Historic District |
| Martinsville Commercial Historic District |
| Martinsville Northside Historic District |
| Martinsville Sanitarium |
| Martinsville Vandalia Depot |
| Masonic Temple |
| Masonic Temple |
| Masonic Temple |
| Masonic Temple |
| Massachusetts |
| Massachusetts Avenue Commercial District |
| Mattison, Donald M., House |
| Mayfield, Leroy, House |
| Mayleeno |
| McCall Family Farmstead |
| McCallum, William, House |
| McClain, John W., House |
| McClelland-Layne House |
| McColloch-Weatherhogg Double House |
| McCormack-Bowman House |
| McCormick Cabin Site |
| McCormick, Charles, Building |
| McCulloch, Hugh, House |
| McCurdy Building (Sears, Roebuck and Company Building) |
| McCurdy Hotel |
| McDoel Historic District |
| McDonald, James and Lucinda, House |
| McEwen-Samuels-Marr House |
| McGill, Charles S. and Mary, House |
| McHaffie, Melville F., Farm |
| McJohnston Chapel and Cemetery |
| McKay |
| McKinley School |
| McNamee-Ford House |
| Mead Johnson River-Rail-Truck Terminal and Warehouse |
| Meeks Avenue Historic District |
| Meier, George Philip, House |
| Melodeon Hall |
| Memorial Park |
| Merchants National Bank and Annex |
| Meridian-Forest Historic District |
| Meridian Park Historic District |
| Merit-Tandy Farmstead |
| Merom-Gill Township Carnegie Library |
| Merrifield-Cass House |
| Messick Masonic Temple |
| Metamora Historic District |
Data from United States Park Service and Wikidata
