The Liberty Hall Museum in Union, Union County, New Jersey, United States, is an American historic site. Built in 1772 as a fourteen-room Georgian-style house, Liberty Hall stands today a fifty-room Victorian Italianate mansion. Liberty Hall has been home to many historical figures and was the home of William Livingston, the first Governor of New Jersey, who served from 1776 to 1790; United States Supreme Court Justice Henry Brockholst Livingston; the Kean political dynasty, including Susan Livingston Kean, widow of Continental Congress delegate John Kean, United States Senator and Congressman John Kean, and Captain John Kean, son of United States Senator Hamilton Fish Kean; and, in its first year of occupancy, future Treasury Secretary Alexander Hamilton.