Castle Clinton or Fort Clinton, previously known as Castle Garden, is a circular sandstone fort located in Battery Park, in Manhattan, New York City. Built from 1808 to 1811, it was the first American immigration station, where more than 8 million people arrived in the United States from 1855 to 1890. Over its active life, it has also functioned as a beer garden, exhibition hall, theater, and public aquarium. Castle Clinton National Monument was listed on the National Register of Historic Places on October 15, 1966.