Massachusetts - Criteria: C (architecture/engineering)
| L.H. Hamel Leather Company Historic District |
| Libby, Nelson F., House |
| Liberty Hall |
| Liberty Tree District |
| Lightship No. 114 |
| Lincoln, Ambrose, Jr., House |
| Lincoln, Asa, House |
| Lincoln Center Historic District |
| Lincoln Estate-Elm Park Historic District |
| Lincoln, Gen. Thomas, House |
| Lincoln, Gov. Levi, House |
| Lincoln Historic District |
| Lincoln House Club |
| Lincolnshire, The |
| Lincoln-Sunset Historic District |
| Linden Street Bridge |
| Lindsey, William, House |
| Linwood Historic District |
| Littlefield-Roberts House |
| Livermore, William, House |
| Locke, Asa, House |
| Locke-Baldwin-Kinsley House |
| Locke, Capt. Josiah, House |
| Locke, Lt. Benjamin, Store |
| Locke-Ober Restaurant |
| Locke School |
| Lockhardt, Charles H., House |
| Lockville Historic District |
| Longfellow House-Washington’s Headquarters National Historic Site |
| Long Island Head Light |
| Longmeadow Historic District |
| Longmeadow Street-North Historic District |
| Long Plain Friends Meetinghouse |
| Long Plain School |
| Long Point Light Station |
| Longwood Historic District |
| Lord-Baylies-Bennett House |
| Lord's Castle |
| Loring, George, House |
| Loring-Greenough House |
| Loring, Harrison, House |
| Lothrop, Caleb, House |
| Lothrop, H.B., Store |
| Lothrop, Joseph, House |
| Lothrop Memorial Building-G.A.R. Hall |
| Lovejoy, A. L., House |
| Lovejoy, Charles, House |
| Lovell Block |
| Lovell, Capt. George, House |
| Lovell, Nehemiah, House |
| Lovering, Joseph, House |
| Lowell Cemetery |
| Lowell Locks and Canals Historic District |
| Lowell National Historical Park |
| Lowell Post Office |
| Lowell's Boat Shop |
| Lowell School |
| Lowell, The |
| Lower Highlands Historic District |
| Lower Historic District |
| Lower Pleasant Street District |
| Lower Roxbury Historic District |
| Lower Union Street Historic District |
| Lowney Chocolate Factory |
| Low, Thomas, House |
| Ludlow Center Historic District |
| Ludlow Village Historic District |
| Luke, Arthur F., House |
| Lumb, Thomas, Three-Decker |
| Lumb, Thomas, Three-Decker |
| LUNA (tugboat) |
| Lundberg, Charles, Three-Decker |
| Lunenburg Historic District |
| Luther House |
| Luther's Corner |
| Luther Store |
| Luther, William, House |
| Lyman Block |
| Lyman School for Boys |
| Lyman Street Historic District |
| Lyman, Theodore, School |
| Lynch-O'Gorman House |
| Lynn, Armory |
| Lynn Bank Block |
| Lynn Common Historic District |
| Lynn Fells Parkway, Metropolitan Park System of Greater Boston |
| Lynn Masonic Hall |
| Lynn Memorial City Hall and Auditorium |
| Lynn Public Library |
| Lynn Realty Company Building No. 2 |
| Lynnwood |
| Lynn Woods Historic District |
| Lyon, T.U., House |
| Machine Shop Village District |
| Macomber, Calvin T., House |
| Macy-Colby House |
| Magnuson, Charles, Three-Decker |
| Mahaiwe Block |
| Main Street Cemetery |
| Main Street Historic District |
Data from United States Park Service and Wikidata
