Geography
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 331,210 km2 (127,881 sq mi)[8] or 331,699 km2 (128,070 sq mi).[9] 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.[180] 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.[181] 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,[182] and tropical forests cover around 42%.[183] The Red River Delta in the north, a flat, roughly triangular region covering 15,000 km2 (5,792 sq mi),[184] 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.[185][186] 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.[187][188] The exclusive economic zone of Vietnam covers 417,663 km2 (161,261 sq mi) in the South China Sea.[189]
Southern Vietnam is divided into coastal lowlands, the mountains of the Annamite Range, and extensive forests. Comprising five relatively flat plateaus of basalt soil, the highlands account for 16% of the country's arable land and 22% of its total forested land.[190] The soil in much of the southern part of Vietnam is relatively low in nutrients as a result of intense cultivation.[191] Several minor earthquakes have been recorded.[192][193] The northern part of the country consists mostly of highlands and the Red River Delta. Fansipan (also known as Phan Xi Păng), which is located in Lào Cai province, is the highest mountain in Vietnam, standing 3,143 m (10,312 ft) high.[194] From north to south Vietnam, the country also has numerous islands; Phú Quốc is the largest.[195] The Hang Sơn Đoòng Cave is considered the largest known cave passage in the world since its discovery in 2009. The Ba Bể Lake and Mekong River are the largest lake and longest river in the country.[196][197][198]