Maryland - Role: Building
| Keedy House |
| Keefer-Brubaker Farm |
| Kefauver Place |
| Kennersley |
| Kernan, James Lawrence, Hospital |
| Kingston |
| Kingston Hall |
| Kirk, Elisha, House |
| Kitterman-Buckey Farm |
| Klots Throwing Company Mill |
| Knipp, George, & Brother Building |
| Knocks Folly |
| Koons, Jacob, Farm |
| Koon, Thomas, House |
| Krieger, Seymour, House |
| Krug Iron Works |
| La Grange |
| LaGrange |
| Lake Drive Apartments |
| Langley Park |
| Lankford House |
| Lansdowne |
| Lantz-Zeigler House |
| Larkin's Hill Farm |
| Larkin's Hundred |
| Laurel High School |
| Laurel Railroad Station |
| La Vale Tollgate House |
| La Veille |
| Lawn, The |
| Layton House |
| Leadenhall Street Baptist Church |
| Legg's Dependence |
| Leverton, Jacob and Hannah, House |
| Lewis Mill Complex |
| Lexon |
| Liberty Hall |
| Linchester Mill |
| Linden |
| Linden |
| Linden Grove |
| Lindens, The |
| Linganore Farm |
| Linnwood |
| Linthicum Walks |
| Lion Brothers Company Building |
| Liriodendron |
| Little Elk Farm |
| Little Falls Meetinghouse |
| Llandaff House |
| Lloyd Street Synagogue |
| Loats Female Orphan Asylum of Frederick City |
| Locust Grove |
| Londontown Manufacturing Company, Inc. |
| London Town Publik House |
| Long Hill |
| Long Island Farm |
| Long Meadows |
| Lord Baltimore Hotel |
| Lore, J. C., Oyster House |
| Lorraine Park Cemetery Gate Lodge |
| Lovely Lane Methodist Church |
| Lowe, Joshua, House |
| Lyons, Joseph D., House |
| Lyric Theatre |
| MacAlpine |
| Maddox, George, Farm |
| Maddux House |
| Madison Avenue Methodist Episcopal Church |
| Magnolia Plantation |
| Maidstone |
| Makemie Memorial Presbyterian Church |
| Make Peace |
| Mannheim |
| Manokin Presbyterian Church |
| Mansion House |
| Maple Leaf Farm Potato House |
| Maples, The |
| Marble Head |
| Marenka House |
| Marietta |
| Markell, George, Farmstead |
| Market Master's House |
| Marley Neck Rosenwald School |
| Marshall Hall |
| Marsh Mills |
| Martin, James, House |
| Mar-Va Theater |
| Maryland Statehouse |
| Maryland Theatre |
| Maryland White Lead Works |
| Mary's Mount |
| Mattapax |
| Maxwell Hall |
| Maynard, Thomas, House |
| McCauley, Henry, Farm |
| McCollum, Elmer V., House |
| McComas Institute |
| McKim's School |
| McMurray-Frizzell-Aldridge Farm |
Data from United States Park Service and Wikidata
