Loudon Park National Cemetery is a United States National Cemetery located in the city of Baltimore, Maryland. It encompasses 5.2 acres (2.1 ha), and as of the end of 2005, had 7,138 interments. It is currently closed to new interments, and is maintained by the Baltimore National Cemetery.
Loudon Park National Cemetery was originally established as a plot within the Loudon Park Cemetery. It was one of the 14 original National Cemeteries established under the National Cemetery Act on July 17, 1862. Most of the original interments were from area veteran hospitals. During the American Civil War, Fort McHenry was a prisoner of war camp, and the prisoners who died while incarcerated there were interred at Loudon Park National Cemetery.
Land acquisitions in 1874, 1875, 1882, 1883 and lastly in 1903, brought the cemetery to its current size.
Loudon Park National Cemetery was placed on the National Register of Historic Places in 1996.