| Korvettes Department Store | Baltimore | MD |
| Kuniang | Baltimore | MD |
| Lafayette Court Apartments | Baltimore | MD |
| Lalande | Baltimore | MD |
| Lamond Private Siding | Takoma Park | MD |
| Landover Mall | Landover | MD |
| Langley's Boat Yard | Solomons | MD |
| Lansburgh Department Store | Langley Park | MD |
| Lansdowne Elementary School | Owings Mills | MD |
| Lansdowne Elementary School | Salisbury | MD |
| La Plata Hospital | La Plata | MD |
| Laurel Race Track | Laurel | MD |
| Lebore | Sparrows Point | MD |
| Legum Distributors | Baltimore | MD |
| Lehigh Cement | Union Bridge | MD |
| Lehigh Portland Cement | Woodsboro | MD |
| Lehigh Portland Cement | Union Bridge | MD |
| Leo J Duster | Baltimore | MD |
| Leroy Insulation | Baltimore | MD |
| Lever Brothers | Baltimore | MD |
| Lever Brothers | Sparrows Point | MD |
| Lewis Emery Jr | Baltimore | MD |
| Lexington Street Apartments | Baltimore | MD |
| Lexington Terrace Apartments | Baltimore | MD |
| LHNCBC | Bethesda | MD |
| Liberty Place Apartments | Baltimore | MD |
| Lithol | Baltimore | MD |
| Little Sisters Of The Poor Nursing Home | Baltimore | MD |
| Litton Industries | College Park | MD |
| Loch Raven Apartments | Baltimore | MD |
| Loch Raven High School | Baltimore | MD |
| Locke Insulators | Baltimore | MD |
| Locust Point | Baltimore | MD |
| Lombard Junior High School | Baltimore | MD |
| Lord Baltimore Press | Baltimore | MD |
| Lord Delaware | Baltimore | MD |
| Louisa M. Alcott | Baltimore | MD |
| Louis Kossuth | Baltimore | MD |
| Louis Yaekel Building | Baltimore | MD |
| Lower Yard | Baltimore | MD |
| Lt. Raymond O. Beaudoin | Baltimore | MD |
| Lucille Bloomfield | Baltimore | MD |
| Lumber Carrier | Baltimore | MD |
| Lynchburg Victory | Baltimore | MD |
| Lynn Victory | Baltimore | MD |
| Maces Lane School | Cambridge | MD |
| Mack Trucks | Hagerstown | MD |
| Main Post Office | Baltimore | MD |
| Manganese Chemical | Baltimore | MD |
| Margaret Brent | Baltimore | MD |
