Completed in 1811, Castle Williams represents the state of the

art in fortifications for its time and influenced the design of

coastal defenses for the next fifty years.In 1901, Secretary of War Elihu Root, who worked hard to modernize the Army, also made a commitment to preserve the castle and overruled army leaders who wanted to demolish both it and Fort Jay. By 1903, the castle was fitted up as a model, state-of-the-art prison facility.