Pier A (also known as City Pier A) is a pier in the Hudson River at Battery Park in Lower Manhattan, New York City. It was built from 1884 to 1886 as the headquarters of the New York City Board of Dock Commissioners and the New York City Police Department (NYPD)'s Harbor Department. Pier A is the only remaining masonry pier in New York City. Above the pier is a two- and three-story building designed by George Sears Greene Jr., with a clock tower facing the Hudson River. The pier is a New York City designated landmark and is listed on the National Register of Historic Places (NRHP).