Fukuoka Castle, also known as Maizuru Castle or Seki Castle, is a historic site located in Chūō-ku, Fukuoka, Japan. Completed in the early Edo period for the daimyō Kuroda Nagamasa, it was once the largest castle in the Kyūshū region. Today, much of the castle grounds have been transformed into Maizuru Park, which includes sports facilities, a courthouse, and an art museum. Visitors can still see some of the castle's gates, towers, and turrets, preserved within the park.