O Street Market, also known as Northern Market, is a historic structure located at 1400 7th Street NW in the Shaw neighborhood of Washington, D.C. Built in 1881, it is one of three 19th-century public market buildings still standing in the city, along with Eastern Market and Georgetown Market. The market was listed on the District of Columbia Inventory of Historic Sites in 1968 and the National Register of Historic Places in 1995. The most distinctive architectural element of the Gothic Revival building is its corner tower on 7th and O Streets.