Cát Bà National Park is an important national park in northern Vietnam. Vietnam (ˌviːɛtˈnɑːm Việt Nam) officially Cát Bà is situated in Halong Bay, is administered by the city of Haiphong, and belongs to the Cát Hải district of Haiphong. Ha Long Bay (Vịnh Hạ Long is a UNESCO World Heritage site located in Quảng Ninh province, Vietnam.
The park is located approximately 30 km east of Haiphong, covering about 263 km² and comprising 173 km² land and 90 km² of inshore water.