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.

By the 20th century, the quality of Battery Park had started to decline, and several new structures were proposed within the park, many of which were not built. In 1940, the entirety of Battery Park was closed for twelve years due to the construction of the Brooklyn–Battery Tunnel and the Battery Park Underpass. The park reopened in 1952 after a renovation, but then subsequently went into decline. The Battery Conservancy, founded in 1994 by Warrie Price, underwrote and funded the restoration and improvement of the once-dilapidated park. In 2015, the Conservancy restored the park's historical name, "the Battery".

The area was originally occupied by the Lenape Native Americans. Dutch settlers populated the area as part of the settlement of New Amsterdam in the early 17th century. The Dutch referred to the southern tip of Manhattan as "Capske Hook" or "Capsie Hoek", the term coming from the Lenape word "Kapsee", meaning "rocky ledge". Capske Hook was originally a narrow, hilly ledge that extended northward to Broadway, which at the time was a Lenape trail. Schreyers Hook (cf. Amsterdam's Schreierstoren) was just adjacent. In 1625–1626, the Dutch built Fort Amsterdam atop of a hill at the site of the present Alexander Hamilton U.S. Custom House. However, the fort was largely ineffective, despite several attempts at reconstruction.

The English took over the settlement in 1664 and renamed the defenses Fort James. An artillery battery was installed at the fort in 1683 by Governor Thomas Dongan, the first of a series of batteries put in around King William's War, which gave the area its name. Other batteries were installed at Whitehall and at Oyster Pasty; the English sometimes used the same name to refer to all of these batteries. Fort Amsterdam would be renamed several times before the British settled on the name of "Fort George" by 1714.

The Battery did not fire any additional shots until 1776, during the New York and New Jersey campaign of the American Revolutionary War, when American troops commandeered the fort and fired on British ships in an unsuccessful attempt to prevent them from sailing up the Hudson River. Following the British landing at Kip's Bay on September 15, 1776, the Americans had abandoned the fort, and the British took Lower Manhattan. At the end of the war in 1783, the Battery was the center of Evacuation Day celebrations commemorating the departure of the last British troops in the United States; the event was later commemorated with the erection of a flagstaff. By 1788, Fort George had been demolished, and debris from the fort was used to expand the Battery. The fort itself became the site of Government House, an executive mansion intended for U.S. president George Washington, though never actually used for that purpose.

In 1808–1811, just prior to the War of 1812, the West Battery was erected on a small artificial offshore island nearby, to replace the earlier batteries in the area. At the time, the shore at the Battery was a relatively flat edge. The West Battery was never used, and following the war, the artillery battery was renamed Castle Clinton. When Battery Park's landmass was created, it encircled and incorporated the island. About 3 acres (1.2 ha) were added to the park area in 1824. Meanwhile, Castle Clinton was turned over to the city government, which turned the structure into an entertainment venue. It subsequently served various purposes, including as an immigration and customs center as well as an aquarium.

By the 1840s, members of the city's elite were publicly calling for the construction of a new large park in Manhattan. Proponents said that the park would serve three purposes: abetting good health, improving the behavior of the "disorderly classes", and showcasing the refinement of the city's elite. At the time, Manhattan's seventeen squares comprised a combined 165 acres (67 ha) of land, the largest of which was the 10-acre (4.0 ha) park at the Battery. Two sites were considered for a large park: Jones's Wood, and the present site of Central Park. An alternate suggestion was to enlarge the existing Battery Park, a move endorsed by most of the public. However, the expansion of Battery Park was opposed by wealthy merchants who deemed the proposed enlargement to be dangerous to maritime traffic, and they obtained the opinion of a United States Navy lieutenant who agreed with them. As a compromise, New York City's aldermen also voted to expand Battery Park to 24 acres (9.7 ha). Ultimately, the plans for the large park would result in the construction of Central Park.