New York Aquarium in the context of "Bronx Zoo"

Castle Clinton (also known as Fort Clinton and Castle Garden) is a restored circular sandstone fort within Battery Park at the southern end of Manhattan in New York City, United States. Built from 1808 to 1811, it was the first American immigration station, predating Ellis Island. More than 7.5 million people arrived in the United States at Fort Clinton between 1855 and 1890. Over its active life, it has also functioned as a beer garden, exhibition hall, theater, and public aquarium. The structure is a New York City designated landmark and a U.S. national monument, and it is listed on the National Register of Historic Places.

Fort Clinton was originally known as the West Battery or the Southwest Battery, occupying an artificial island off the shore of Lower Manhattan. Designed by John McComb Jr., with Jonathan Williams as consulting engineer, the fort was garrisoned in 1812 but was never used for warfare. In 1824, the New York City government converted Fort Clinton into a 6,000-seat entertainment venue known as Castle Garden, which operated until 1855. Castle Garden then served as an immigrant processing depot for 35 years. When the processing facilities were moved to Ellis Island in 1892, Castle Garden was converted into the first home of the New York Aquarium, which opened in 1896 and continued operating until 1941. The fort was expanded and renovated several times during this period.

The Battery, formerly known as Battery Park, is a 25-acre (10 ha) public park located at the southern tip of Manhattan Island in New York City facing New York Harbor. The park is bounded by Battery Place on the north, with Bowling Green to the northeast, State Street on the east, New York Harbor to the south, and the Hudson River to the west. The park contains attractions such as an early 19th-century fort named Castle Clinton; multiple monuments; and the SeaGlass Carousel. The surrounding area, known as South Ferry, contains multiple ferry terminals, including the Staten Island Ferry's Whitehall Terminal; a boat launch to the Statue of Liberty National Monument (which includes Ellis Island and Liberty Island); and a boat launch to Governors Island.

The park and surrounding area are named for the artillery batteries that were built in the late 17th century to protect the fort and settlement behind them. By the 1820s, the Battery had become an entertainment destination and promenade, with the conversion of Castle Clinton into a theater venue. During the mid-19th century, the modern-day Battery Park was laid out and Castle Clinton was converted into an immigration and customs center. The Battery was commonly known as the landing point for immigrants arriving in New York City until 1892, when the immigration center was relocated to Ellis Island in the middle of the harbor. Castle Clinton (sometimes called, Castle Garden) then hosted the New York Aquarium from 1896 to 1941.