Osaka Castle Park (大阪城公園, Osaka-Jō-Kōen) is a public urban park and historical site situated at Osaka-Jō in Chūō-ku, Osaka, Japan.It lies on the south of the Ōkawa (Kyū-Yodo River) and occupies a large area in the center of the city of Osaka. This park is the second largest park in the city.