Maine - Criteria: A (event)
| LEWIS R. FRENCH (schooner) |
| Lewiston Mills and Water Power System Historic District |
| Lewiston Public Library |
| Libby Island Light Station |
| Libby's Colonial Tea Room |
| Liberty Hall |
| Lightship No. 112, NANTUCKET |
| Limerick Upper Village Historic District |
| Limington Academy |
| Limington Historic District |
| Lincoln School |
| Lion, The (locomotive) |
| Little, Edward, House |
| Littlefield-Chase Farmstead |
| Littlefield-Dustin Farm |
| Littlefield Homestead |
| Littlefield Tavern |
| Little Mark Island Monument |
| Little Red Schoolhouse |
| Little River Light Station |
| Lockwood Mill Historic District |
| Longfellow, Stephen, House |
| Long, Zadoc, Free Library |
| Lord Farm |
| Lord Mansion |
| Lovejoy Bridge |
| Lovell Meeting House |
| Lovell Village Church |
| Lower Alewive Historic District |
| Lower Lisbon Street Historic District |
| Lower Sunday River School |
| Low, Joseph W., House |
| Lubec Channel Light Station |
| Lucerne Inn |
| Ludwig, Godfrey, House |
| 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 Historical Society |
| Maine Industrial School for Girls Historic District |
| Maine Publicity Bureau Building |
| Maine State House |
| Maine Trolley Cars |
| Maine Woods Office |
| Main Street-Frye Street Historic District |
| Main Street Historic District |
| Main Street Historic District |
| Mallett Hall |
| Mallett Hall |
| Manana Island Fog Signal Station |
| Mann, Arthur L., Memorial Library |
| Manor House |
| Mansion House, The |
| Maplewood Farm |
| Marcotte Nursing Home |
| Marine Hospital |
| Mariner's Church |
| Market Square Historic District |
| Marrett, Daniel, House |
| Marshall Point Light Station |
| Marsh School |
| Marsh Stream Farm |
| Masonic Temple |
| Massachusetts Hall, Bowdoin College |
| Matinicus Rock Light Station |
| McCleary Farm |
| McCobb-Hill-Minott House |
| McCurdy Smokehouse |
| Means, Emily, House |
| Mechanic Institute |
| Memorial Hall |
| Mequnticook Golf Club |
| MERCANTILE (schooner) |
| Merrill, Capt. Reuben, House |
| Merrill-Poor House |
| Mill Agent's House |
| Mill at Freedom Falls |
| Mill Cove School |
| Mill House |
| Milo Public Library |
| Monhegan Island Lighthouse and Quarters |
| Monson Community Church |
| Monson Engine House (Former) |
| Monticello Grange #338 |
| Montville Town House |
| Moore, Henry D., Parish House and Library |
| Moore, John, House |
| Morse & Co. Office Building |
| Mortland Family Farm |
| Mount Desert Light Station |
| Mount Hope Cemetery District |
| Mt. Battie Tower |
| Municipal Building |
| Murch Family House |
| Narraguagus Light Station |
| Nelson Family Farm |
| Newfield (Willowbrook) Historic District |
Data from United States Park Service and Wikidata
