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Castle Williams: A Harbor Fortress with a Storied Past

Explore Castle Williams on Governors Island: a historic fortress with stunning views, offering a glimpse into New York's coastal defense and military history.

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Castle Williams, a circular sandstone fortress on Governors Island in New York Harbor, was built between 1807 and 1811. Designed by Lt. Col. Jonathan Williams, it served as a prototype for coastal fortifications and later as a military prison, offering stunning views of the Manhattan skyline.

A brief summary to Castle Williams

Local tips

  • Check the Governors Island ferry schedule in advance, as service varies by season.
  • Access to the first floor and outdoor exhibits is free and self-guided.
  • Guided tours of the upper levels are sometimes available, but tickets are limited and require advance booking.
  • Bring water and snacks, as options on Governors Island can be limited.
  • Wear comfortable shoes for walking around the island and exploring the castle.
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Getting There

  • Ferry

    The primary way to reach Castle Williams is by taking the Governors Island Ferry. Ferries depart from Battery Maritime Building in Lower Manhattan and from Brooklyn. Check the official website for the most up-to-date schedules and departure locations, as they can vary depending on the season. The ferry ride itself offers excellent views of the harbor. Once on Governors Island, Castle Williams is a short walk from the ferry terminal. Ferry tickets are around $4 for adults; however, the ferry is free on weekends before noon.

  • Walking

    Once you arrive on Governors Island via ferry, Castle Williams is located on the western side of the island. From the ferry terminal, follow the signs towards the western promenade. The walk is approximately 10-15 minutes and offers scenic views of the harbor and Lower Manhattan. The path is mostly flat and paved, making for an easy stroll. As you approach the castle, you'll see it's imposing circular structure made of red sandstone.

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Discover more about Castle Williams

Castle Williams, a striking circular defensive structure made of red sandstone, stands on the western edge of Governors Island in New York Harbor. Constructed between 1807 and 1811, the castle was designed by Lt. Col. Jonathan Williams, Chief Engineer of the US Army Corps of Engineers, for whom it is named. It was intended as a key component of the harbor's defense system, protecting New York City from naval attacks. Its design was innovative for the time, serving as a prototype for future coastal fortifications. The castle's walls, built from red Newark sandstone with a granite parapet, were designed to withstand cannon fire. The first two tiers each had 26 embrasures for cannons, while the third tier housed troops and additional gun emplacements. The strength of Castle Williams, along with nearby Fort Jay and Castle Clinton in Manhattan, deterred British attacks during the War of 1812. Over the years, Castle Williams has served various purposes. By the 1830s, its role as a primary fort diminished, and it was repurposed as barracks for the island's garrison. During the Civil War and for much of the 20th century, the U.S. Army used it as a military prison, housing Confederate prisoners of war and political prisoners. In 1903, it was modernized as a state-of-the-art prison facility. After ceasing operations as a military prison in 1965, it narrowly escaped demolition and was briefly a community center before becoming a grounds-keeping shop for the Coast Guard. Today, Castle Williams is part of the Governors Island National Monument, managed by the National Park Service. Visitors can explore the ground level of the castle, view exhibits detailing its history, and enjoy panoramic views of the harbor and the Manhattan skyline.

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