Covering an area of 10,000 hectares in the northeast of Ninh Binh province, Trang An includes three individual components within a single buffer zone that are Trang An Ecological Area, Tam Coc-Bich Dong River Landscape and Hoa Lu Ancient Citadel. The Trang An Trang An Eco-Tourism Complex is situated inland on the coastal plain of within the highly eroded limestone block of Hoa Lu, part of the Truong Yen – Bich Dong mountain range. This range comprised of by limestone karst peaks of high fragmentation forming low mountains separated by valley floors composed of sedimentary rock, where shales predominate.