Maryland - Criteria: A (event)
| Kefauver Place |
| Kensington Historic District |
| Kernan, James Lawrence, Hospital |
| Kingston |
| Kitterman-Buckey Farm |
| Klots Throwing Company Mill |
| Koons, Jacob, Farm |
| Krug Iron Works |
| Lake Drive Apartments |
| Lake-Evesham Historic District |
| Lake Roland Historic District |
| Larkin's Hill Farm |
| Larkin's Hundred |
| Lauraville Historic District |
| Laurel High School |
| Laurel Railroad Station |
| La Vale Tollgate House |
| Lawyers Hill Historic District |
| Layton House |
| Leadenhall Street Baptist Church |
| LeGore Bridge |
| Lehman's Mill Historic District |
| Leitersburg Historic District |
| Leverton, Jacob and Hannah, House |
| Lewis Mill Complex |
| Linchester Mill |
| Linganore Farm |
| Linthicum Heights Historic District |
| Linwood Historic District |
| Lion Brothers Company Building |
| Little Falls Meetinghouse |
| Little Montgomery Street Historic District |
| Lloyd Street Synagogue |
| Locust Point Historic District |
| Loft Historic District North |
| Loft Historic District South |
| Lombard Street Bridge |
| Lonaconing Furnace |
| Lonaconing Historic District |
| Londontown Manufacturing Company, Inc. |
| Long Green Valley Historic District |
| Long Island Farm |
| Long Meadows |
| Lord Baltimore Hotel |
| Lore, J. C., Oyster House |
| Lorraine Park Cemetery Gate Lodge |
| Loudon Park National Cemetery |
| Lovely Lane Methodist Church |
| Lowe, Joshua, House |
| Lower Deer Creek Valley Historic District |
| Loys Station Covered Bridge |
| Lutherville Historic District |
| Lyric Theatre |
| Maddox, George, Farm |
| Maddux House |
| MAGGIE LEE |
| MAGIC (log canoe) |
| Mannheim |
| Manokin Historic District |
| Manokin Presbyterian Church |
| Mansion House |
| Marenka House |
| Markell, George, Farmstead |
| Market Center |
| Market Master's House |
| Marley Neck Rosenwald School |
| Marshall Hall |
| Marsh Mills |
| MARTHA LEWIS (skipjack) |
| Maryland Statehouse |
| Maryland Theatre |
| Maryland White Lead Works |
| MARY W.SOMERS (Chesapeake Bay skipjack) |
| Mason and Dixon West Line Milestone Markers 76 and 77 |
| Mattapany-Sewall Archeological Site |
| Mayfield Historic District |
| McCauley, Henry, Farm |
| McComas Institute |
| McDonogh Place Historic District |
| McKim's School |
| McPherson's Purchase |
| Melwood Park |
| Mercantile Deposit and Trust |
| Mercantile Trust and Deposit Company |
| Mettam Memorial Baptist Church |
| Middle, East and West Halls |
| Middleham Chapel |
| Middletown Historic District |
| Miller, H.F. Miller & Son Tin Box and Can Manufacturing Plant |
| Miller's House |
| Mill Green Historic District |
| Milton |
| MINNIE V |
| Monocacy National Battlefield |
| Montgomery County Courthouse Historic District |
| Montgomery Ward Warehouse and Retail Store |
| Montrose |
| Moreland |
| Morgan State University Memorial Chapel |
| Mountain Lake Park Historic District |
Data from United States Park Service and Wikidata
