New Jersey v. New York, 523 U.S. 767 (1998), was a U.S. Supreme Court case that determined that roughly 83% of Ellis Island was part of New Jersey, rather than New York State. Because the New Jersey's original 1664 land grant was unclear, the states of New Jersey and New York disputed ownership and jurisdiction over the Hudson River and its islands. The two states entered into a compact ratified by Congress in 1834, which set a boundary line to be the middle of the Hudson River, but giving all islands in the river (including Ellis Island) to New York.