Connecticut - Role: Building
| Le Roy Shirt Company Factory |
| Lester, Nathan, House |
| Lester, Timothy, Farmstead |
| Lewis, Isaac C., Cottage |
| Lewis, Isaac, House |
| Lewis-Zukowski House |
| Lighthouse Inn |
| Lincoln Theatre |
| Linden Apartments |
| Linke, William L., House |
| Little Bethel African Methodist Episcopal Church |
| Lockwood-Mathews Mansion |
| Locust Avenue School |
| Long Society Meetinghouse |
| Loomis, Capt. James, House |
| Loomis, Col. James, House |
| Loomis, George G., House |
| Loomis, Gordon, House |
| Loomis, Ira, Jr., House |
| Loomis-Pomeroy House |
| Lord, Capt. Enoch, House |
| Loth, Joseph, Company Building |
| Lounsbury, Phineas Chapman, House |
| Low House |
| Lyman, David, II, House |
| Lyman House |
| Lyman, Thomas, House |
| Lyon, Thomas, House |
| Magill, Henry, House |
| Mallett, David, Jr., House |
| Mansfield, Richard, House |
| Mansuy and Smith Automobile Showroom Building |
| Maplewood School |
| Marion Castle, Terre Bonne |
| Marlborough Congregational Church |
| Marlborough House |
| Marlborough Tavern |
| Marsh, Othniel C., House |
| Martin, Caleb, House |
| Marvin Tavern |
| Masonic Temple |
| Massacoe Forest Pavilion |
| Mather Homestead |
| Mather, Stephen Tyng, House |
| Matthews and Willard Factory |
| Mead Camp |
| Meadowlands |
| Meeker's Hardware |
| Meigs-Bishop House |
| Memorial Hall |
| Mendel, Lafayette B., House |
| Meriden Curtain Fixture Company Factory |
| Merrill, James, House |
| Merritt Beach & Son Building |
| Merryall Union Evangelical Society Chapel |
| Merwinsville Hotel |
| Methodist Episcopal Church |
| Metropolitan African Methodist Episcopal Zion Church |
| Middle Haddam School |
| Middletown Alms House |
| Milford Point Hotel |
| Miller, Henry F., House |
| Mills, Beaven W., House |
| Mills, Elijah, House |
| Mills, Oliver W., House |
| Mills, Timothy Dwight, House |
| Mills, Willis N, House |
| Miner, Samuel, House |
| Mixer Tavern |
| Monte Cristo Cottage |
| Moody, Dr. Mary B., House |
| Moore, Deacon John, House |
| Moore, Edward and Ann, House |
| Moore Jr., William, House |
| Moore, Roswell, II, House |
| Morley, Edward W., House |
| Morris and Rose Greenwald House |
| Morris House |
| Mory's |
| Moseley House-Farm |
| Moss Hill |
| Mount Carmel Congregational Church and Parish House |
| Mount St. Joseph Academy |
| Mulville House |
| Municipal Building |
| Murphy, Charles and Peggy House |
| Murphy, Patrick, House |
| Murray, Jonathan, House |
| Music Mountain |
| Myers and Gross Building |
| Mystic Bank |
| Natchaug Forest Lumber Shed |
| Nehemiah Royce House |
| Neiditz Building |
| New Britain Opera House |
| New Britain Public High School Campus |
| New Haven Armory |
| New Haven City Hall |
| New Haven County Courthouse |
| New Haven Jewish Home for the Aged |
Data from United States Park Service and Wikidata
