Vietnam
is located on the eastern Indochinese Peninsula between the latitudes 8° and 24°N, and the longitudes 102° and 110°E. It covers a total area of approximately 331,212 km2 (127,882 sq mi). The combined length of the country's land boundaries is 4,639 km (2,883 mi), and its coastline is 3,444 km (2,140 mi) long. At its narrowest point in the central Quảng Bình Province, the country is as little as 50 kilometres (31 mi) across, though it widens to around 600 kilometres (370 mi) in the north.
Vietnam's land is mostly hilly and densely forested, with level land covering no more than 20%. Mountains account for 40% of the country's land area, and tropical forests cover around 42%. The Red River Delta in the north, a flat, roughly triangular region covering 15,000 km2 (5,792 sq mi), is smaller but more intensely developed and more densely populated than the Mekong River Delta in the south. Once an inlet of the Gulf of Tonkin, it has been filled in over the millennia by riverine alluvial deposits. The delta, covering about 40,000 km2 (15,444 sq mi), is a low-level plain no more than 3 metres (9.8 ft) above sea level at any point. It is criss-crossed by a maze of rivers and canals, which carry so much sediment that the delta advances 60 to 80 metres (196.9 to 262.5 ft) into the sea every year. The exclusive economic zone of Vietnam covers 417,663 km2 (161,261 sq mi) in the South China Sea.