<Tr> <Th> State </Th> <Td> New York </Td> </Tr> <Tr> <Th> County </Th> <Td> Suffolk County </Td> </Tr> <P> Gardiner's Island is a small island in the Town of East Hampton, New York, in Eastern Suffolk County . It is located in Gardiner's Bay between the two peninsulas at the East end of Long Island . It is 6 miles (9.7 km) long, 3 miles (4.8 km) wide and has 27 miles (43 km) of coastline . The island has been owned by the Gardiner family and their descendants since 1639 when Lion Gardiner purchased it from the Montaukett chief Wyandanch . It is one of the larger privately owned islands in the United States, and is slightly smaller than Naushon Island in Massachusetts, owned by the Forbes Family . </P> <P> The island is 3,318 acres (1,343 ha) in size . It includes more than 1,000 acres (400 ha) of old growth forest and another 1,000 acres (405 ha) of meadows . Many of the buildings date back to the 17th century . In 1989, the island was said to be worth $125 million . </P>

Largest privately owned island in the united states