Governors Island is a 172-acre (70 ha) island in Upper New York Bay, approximately one-half mile (1 km) from the southern tip of Manhattan Island and separated from Brooklyn by Buttermilk Channel. It is legally part of the borough of Manhattan in New York City. Physically, the island changed greatly during the early 20th century. Using material excavated from the Lexington Avenue subway, the Army Corps of Engineers supervised the deposit of 4,787,000 cubic yards of fill on the south side of Governors Island, adding 103 acres (42 ha) of flat, treeless land by 1912 and bringing the total acreage of the island to 172.

The Native Americans of the Manhattan region referred to the island as "Paggank", meaning 'nut island', doubtless after the island's plentiful hickory, oak, and chestnut trees; the Dutch explorer Adriaen Block called it "Noten Eylant", a translation, and this was borrowed into English as "Nutten Island". The island's current name, made official in 1784, stems from British colonial times when the colonial assembly reserved the island for the exclusive use of New York's royal governors.

Defensive works were raised on the island in 1776 by Continental Army troops during the American Revolutionary War, and fired upon British ships before they were taken. From 1783 to 1966, the island was a United States Army post. From 1966 to 1996 the island served as a major United States Coast Guard installation.