The exactly geographical position is in a rectangle between 20°55'05" and 21°15'10" North latitude, 107°30'10" and 107°46'20" East longitude. It administratively consists of 3 communes : Minh Châu, Vạn Yên and Hạ Long of Van Don district.
It is composed from a terrestrial area of 61.25 km2 and an aquatic area of 96.58 km2. The zone includes over 40 islands and rocks. They form three groups : Ba Mùn group, Trà Ngọ group and Sậu group. The aquatic area includes the sea zone between the islands and the narrows between the park area and the land area which has boundary of 1 km offshore. The National Park also includes a buffer zone of approximately 165.34 km2, which is located in a larger area including 5 communes : Minh Châu, Vạn Yên, Bản Sen, Quan Lạn and Hạ Long. The total population of the core zone and the buffer zone is around 24.000.
The National Park includes five kinds of ecosystems : Rain Broad Leaves Forest, Limestone Forest, Littoral Forest, Coral Area and Shallow Water Area.
The Rain Broad Leaves Forest area is mostly secondary forest. The average canopy covers 50 – 90%. 494 species belonging to 337 genera of 117 families have been found in this type of ecosystem. Some endangered species include Cycas balansae, Radix marindae officinalis, Ardisia sylvestris Pitard, Smilax glabra, Leopard cat (Prionailurus bengalensis), Indian muntjac (Muntiacus muntjak), Small Indian civet (Viverricula indica), Large Indian civet (Viverra zibetha).
The Limestone Forest area is forest growing in poor soil with particles of limestone on rocky islands. Some rare animals found there include Serow, Rhesus macaque.
The Littoral Ecosystem in the park is small areas surrounding the islands. It has a rather large tidal variation and is biologically highly diverse with 251 species including 19 species of mangrove, 17 species of seaweed, 29 species of marine worms, 149 species of molluscs, 22 species of crustaceans and 15 species of echinoderms.
The Coral area is located from the water depths of low tide to 10m deep. 409 species have been found including groupers, sea bass, crabs, snails, abalone and seaweeds.
The shallow water area covers a large area around the islands, beyond the tidal area and extending from 1 km to around 4 km. These areas have not been profoundly researched but 539 species have been found.