The Camden Line is a MARC commuter rail line that runs for 39 mi (63 km) between Union Station, Washington, D.C., and Camden Station, Baltimore, Maryland, over the CSX Capital Subdivision and Baltimore Terminal Subdivision. The Baltimore & Ohio Railroad began running commuter service from Baltimore to Ellicott City over part of the current line's trackage on May 24, 1830, making this corridor one of the country's oldest rail routes still in operation. The line was extended to Washington on August 25, 1835. The Camden Line is the shortest MARC line. As of 2019, the Camden Line is a weekday-only service.

Camden Station, now also referred to as Camden Street Station, Camden Yards, and formally as the Transportation Center at Camden Yards, is a train station at the intersection of South Howard and West Camden Streets in Baltimore, Maryland, adjacent to Oriole Park at Camden Yards, behind the B&O Warehouse. It is served by MARC commuter rail service and local Light Rail trains.