Mid-Atlantic Sports Network (MASN) is an American regional sports network owned as a joint venture between two Major League Baseball franchises, the Baltimore Orioles and the Washington Nationals. Headquartered in Baltimore, Maryland, the channel broadcasts regional coverage of sports events in the Washington, D.C., and Baltimore metropolitan areas.

The Washington Nationals are an American professional baseball team based in Washington, D.C. The Nationals compete in Major League Baseball (MLB) as a member of the National League (NL) East Division. From 2005 to 2007, the team played in RFK Stadium while a new stadium was being built. In 2008, they moved to Nationals Park, located on South Capitol Street in the Navy Yard neighborhood of the Southeast quadrant of D.C., near the Anacostia River.