The Trang An Grottoes is Scenic Landscape Complex is located in the districts Hoa Lu, Gia Vien, and Nho Quan of Ninh Binh Province in northern Viet Nam. The heritage property is spread over a large area of 10,000 hectares, and is made up of three individual components within a single buffer zone.
The three components are: the Trang An Ecological Area, (ii) the Tam Coc caves and Bich Dong pagoda, and the Hoa Lu Ancient Citadel. The three areas share a common geological and ecological environment characterized by dramatic limestone karsts, permeated with a network of caves, and bound together by flooded inland waterways of high biological diversity. Together these three contiguous areas comprise the core zone of the heritage property.
To the east of the property is the Chanh River, to the north is the Hoang Long River and to the southwest is the Ben Dang River. The north, east and southeast sides comprise vast flat floodplains formed by Day and Van Rivers.
The crust in the Trang An region has a geologic history of 245 million years and includes six strata from of the Triassic and Quaternary Ages. It includes strata of different thickness, which has facilitated karstification and the formation of the area's unique landscape.
The Trang An Scenic Landscape 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. These valley floors are characterized by a long process of denudation, erosion, and surface runoff which has accumulated as a mixture of aluvi - deluvi - proluvi.