There are more than 1,500 properties and districts listed on the National Register of Historic Places in the U.S. State of Maryland. Each of the state's 23 counties and its one county-equivalent (the independent city of Baltimore) has at least 20 listings on the National Register.
Current listings by county
The following are approximate tallies of current listings in Maryland on the National Register of Historic Places. These counts are based on entries in the National Register Information Database as of April 24, 2008 and new weekly listings posted since then on the National Register of Historic Places web site. There are frequent additions to the listings and occasional delistings, and the counts here are not official. Also, the counts in this table exclude boundary increase and decrease listings which modify the area covered by an existing property or district and which carry a separate National Register reference number.
- List of National Historic Landmarks in Maryland
- List of bridges on the National Register of Historic Places in Maryland
- National Park Service, United States Department of the Interior, "National Register of Historic Places: Weekly List Actions", retrieved May 7, 2021.
- "National Register Information System". National Register of Historic Places. National Park Service. April 24, 2008.
- "National Register of Historic Places: Weekly List Actions". National Park Service. Retrieved January 2, 2009.
- The following sites are listed in multiple counties: Chesapeake and Ohio Canal National Historical Park (Allegany, Frederick, Montgomery and Washington), Dundalk Historic District (Baltimore (city) and Baltimore County), Hopewell (Carroll and Frederick), Inns on the National Road (Allegany and Garrett), Jericho Covered Bridge (Baltimore and Harford), James Lawrence Kernan Hospital (Baltimore (city) and Baltimore County), McKinstry's Mills Historic District (Carroll and Frederick), Mount Airy Historic District (Carroll and Frederick), My Lady's Manor (Baltimore and Harford), Old National Pike Milestones (Alleghany, Baltimore (city), Baltimore County, Carroll, Frederick, Howard and Washington), Patterson Viaduct Ruins (Baltimore and Howard), Thomas Viaduct, Baltimore & Ohio Railroad (Baltimore and Howard), Western Maryland Railroad Right-of-Way, Milepost 126 to Milepost 160 (Alleghany and Washington), Wye Mill (Queen Anne's and Talbot).