Ha Long Bay is a unique area of 'karst' limestone towers that have been inundated by the sea creating nearly two thousand rocky pinnacles protruding up to 200m above sea level. The bay covers just over 1500 km² and its natural resources, coral reefs, sea grass beds, mangroves and marine flora and fauna provide livelihoods for a significant proportion of the residents of Ha Long City and Cam Pha Town, a rapidly developing urban and industrial area with a population exceeding 300,000 immediately adjacent to the WHA.

Abutted by Ha Long City, a vigorously developing industrial and urban area based upon major coal mining, shipping and mineral extraction activities, Ha Long Bay is under threat from water and atmospheric pollution, environmental and cultural degradation and inappropriate urban development.