The United States Post Office Madison Square Station is a historic post office building located at 149 East 23rd Street between Lexington Avenue and Third Avenue on the East Side of Manhattan, New York City. In spite of the building's name, it is not located on Madison Square but about five blocks east (approximately 1/4 mile) along 23rd Street. The building runs through the block to East 24th Street, where there are loading docks and another much smaller and less formal public entrance. The Madison Square Station was listed on the National Register of Historic Places in 1989.