Grand Isle County is one of several Vermont counties created from land ceded by the state of New York on January 15, 1777, when Vermont declared itself to be a distinct state from New York. The land was originally contested by Massachusetts, New Hampshire, New France and New Netherland, but it remained undelineated until July 20, 1764, when King George III established the boundary between New Hampshire and New York along the west bank of the Connecticut River, north of Massachusetts and south of the parallel of 45 degrees north latitude. New York assigned the land gained to Albany County. On March 12, 1772, Albany County was partitioned to create Charlotte County, and this situation persisted until Vermont's independence from New York and Britain, which, however, did not end the contest.