The Hudson River Chain refers to two chain booms and two chevaux de frise constructed from 1776 to 1778 during the American Revolutionary War across the Hudson River as defenses to prevent British naval vessels from sailing upriver. These defenses along the Hudson River were overseen by the Highlands Department of the Continental Army. The most significant and successful was the Great Chain, constructed from West Point in 1778, and used through 1782 after the war's end. The huge links for the chains were forged at iron works in Orange County, New York.