Maryland - Significance region: Local
| Little Falls Meetinghouse |
| Little Montgomery Street Historic District |
| Llandaff House |
| Loats Female Orphan Asylum of Frederick City |
| Locust Grove |
| Locust Point Historic District |
| Loft Historic District North |
| Loft Historic District South |
| Lonaconing Historic District |
| Long Green Valley Historic District |
| Long Island Farm |
| Long Meadows |
| Lord Baltimore Hotel |
| Lore, J. C., Oyster House |
| Lorraine Park Cemetery Gate Lodge |
| Lowe, Joshua, House |
| Lower Deer Creek Valley Historic District |
| Lyons, Joseph D., House |
| Lyric Theatre |
| MacAlpine |
| Maddox, George, Farm |
| Maddux House |
| Madison Avenue Methodist Episcopal Church |
| Magnolia Plantation |
| Magothy Quartzite Quarry Archeological Site |
| Makemie Memorial Presbyterian Church |
| Mannheim |
| Mansion House |
| Maple Leaf Farm Potato House |
| Marble Head |
| Marenka House |
| Marietta |
| Markell, George, Farmstead |
| Market Center |
| Market Master's House |
| Marley Neck Rosenwald School |
| Marsh Mills |
| Martin, James, House |
| Martins Pond Site |
| Mar-Va Theater |
| Maryland Heights, Spur Battery |
| Maryland White Lead Works |
| Mary's Mount |
| Mattapax |
| Mayfield Historic District |
| Maynard, Thomas, House |
| McCandless Archeological Site |
| McCauley, Henry, Farm |
| McComas Institute |
| McDonogh Place Historic District |
| McKinstry's Mills Historic District |
| McMurray-Frizzell-Aldridge Farm |
| McPherson's Purchase |
| Meadow Brook Farm |
| Meadows, The |
| Medicine Hill |
| Melford |
| Memory Lane |
| Mercantile Deposit and Trust |
| Mercantile Trust and Deposit Company |
| Mercy Chapel at Mill Run |
| Merry Sherwood |
| Mesrobian, Mihran, House |
| Middleham Chapel |
| Middletown Historic District |
| Midtown Edmondson Historic District |
| Miller, H.F. Miller & Son Tin Box and Can Manufacturing Plant |
| Miller's House |
| Mill Green Historic District |
| Mitchell, Congressman Parren J., House |
| Mitchell House |
| Montgomery County Courthouse Historic District |
| Montgomery Ward Warehouse and Retail Store |
| Montrose |
| Montrose Mansion and Chapel |
| Montrose Schoolhouse |
| Moreland |
| Morgan Park Historic District |
| Morgan State University Memorial Chapel |
| Motter, John C., House |
| Mount Adams |
| Mount Air |
| Mount Airy |
| Mount Airy |
| Mount Airy Historic District |
| Mount Auburn Cemetery |
| Mount Aventine |
| Mount de Sales Academy |
| Mount Hope |
| Mount Lubentia |
| Mount Rainier Historic District |
| Mount Savage Historic District |
| Mount Vernon Mill No. 1 |
| Mt. Nebo |
| Mt. Pleasant |
| Mt. Tabor Good Samaritan Lodge #59 |
| Mt. Tabor Methodist Episcopal Church |
| Mt. Zion Memorial Church |
| Nallin Farm House |
| Nallin Farm Springhouse and Bank Barn |
Data from United States Park Service and Wikidata
