Maine - Role: Building
| Low, Joseph W., House |
| Lucerne Inn |
| Ludwig, Godfrey, House |
| Lyceum Hall |
| Machias Post Office and Customhouse |
| Machias Railroad Station |
| Machias Valley Grange, #360 (Former) |
| Madison Public Library |
| Madrid Village Schoolhouse |
| Maine Central Railroad General Office Building |
| Maine Experiment Station Barn |
| Maine Eye and Ear Infirmary |
| Maine Historical Society |
| Maine Publicity Bureau Building |
| Maine Spinning Company Mill |
| Maine State Building |
| Maine State House |
| Maine Supply Company Building |
| Maine Women's Reformatory Maternity Hospital and Nursery |
| Maine Woods Office |
| Mallett, E. B., Office Building |
| Mallett Hall |
| Mallett Hall |
| Manley, Joseph and Susan, Summer Cottage |
| Mann, Arthur L., Memorial Library |
| Manning, Richard, House |
| Manor House |
| Mansion House, The |
| Mansur, Walter P., House |
| Manufacturer's National Bank |
| Maple Grove Friends Church |
| Marcotte Nursing Home |
| Marine Hospital |
| Mariner's Church |
| Marrett, Daniel, House |
| Marsh School |
| Martel, Dr. Louis J., House |
| Martin, Isaie and Scholastique, House |
| Mason, Dr. Moses, House |
| Masonic Hall |
| Masonic Temple |
| Masonic Temple |
| Massachusetts Hall, Bowdoin College |
| Maxcy, Joseph and Hannah, Homestead |
| May, Sophie, House |
| McCobb-Hill-Minott House |
| McGilvery, Capt. John, House |
| McGilvery, Capt. William, House |
| McGlashan-Nickerson House |
| McIntire Garrison House |
| McLellan House |
| McLellan-Sweat Mansion |
| McWain-Hall House |
| Means, Emily, House |
| Mechanic Institute |
| Mechanics' Hall |
| Memorial Chapel |
| Memorial Hall |
| Mercer Union Meetinghouse |
| Merriconeag Grange No. 425 |
| Merriconegan Farm |
| Merrill, Capt. Reuben, House |
| Merrill, Capt. Reuel and Lucy, House |
| Merrill Hall |
| Merrill-Poor House |
| Merritt, Captain, House |
| Michaud, Fortunat O., House |
| Milford Congregational Church |
| Mill Agent's House |
| Mill at Freedom Falls |
| Mill Cove School |
| Miller's Garage |
| Mill House |
| Milo Public Library |
| Minott, William, House |
| Mitchell House |
| Monhegan Island Lighthouse and Quarters |
| Monson Community Church |
| Monson Engine House (Former) |
| Monticello Grange #338 |
| Montville Town House |
| Moody Farm |
| Moody Homestead |
| Moody Mansion |
| Moore, Henry D., Parish House and Library |
| Moore, John, House |
| Moore-Mayo House |
| Moose River Congregational Church |
| Morison, Capt. James, House |
| Morrell House |
| Morrill Homestead |
| Morrill, Lot, House |
| Morse & Co. Office Building |
| Morse-Libby Mansion |
| Morse's Corner School |
| Mosquito Island House |
| Municipal Building |
| Munroe, Horace, House |
| Murch Family House |
| Nannau |
Data from United States Park Service and Wikidata
