Vietnam

tropical in south; monsoonal in north with hot, rainy season (May to September) and warm, dry season (October to March)

low, flat delta in south and north; central highlands; hilly, mountainous in far north and northwest

Southeastern Asia, bordering the Gulf of Thailand, Gulf of Tonkin, and South China Sea, as well as China, Laos, and Cambodia

3,444 km (excludes islands)

46,000 sq km (2012)

Southeast Asia

occasional typhoons (May to January) with extensive flooding, especially in the Mekong River delta

note 1: extending 1,650 km (1,025 mi) north to south, the country is only 50 km (31 mi) across at its narrowest point note 2: Son Doong in Phong Nha-Ke Bang National Park is the world's largest cave (greatest cross-sectional area) and is the largest known cave passage in the world by volume at 38.5 million cu m (about 1.35 billion cu ft); it connects to Thoong cave, but not yet officially -- when recognized, it will add an additional 1.6 million cu m; it is so massive that it contains its own jungle, underground river, and localized weather system, with clouds forming inside the cave and spewing from its exits

antimony, phosphates, coal, manganese, rare earth elements, bauxite, chromate, offshore oil and gas deposits, timber, hydropower, arable land

about three times the size of Tennessee; slightly larger than New Mexico

16 10 N, 107 50 E

though it has one of the highest population densities in the world, the population is not evenly dispersed; clustering is heaviest along the South China Sea and Gulf of Tonkin, with the Mekong Delta (in the south) and the Red River Valley (in the north) having the largest concentrations of people

Sông Tiên Giang (Mekong) river mouth (shared with China [s], Burma, Laos, Thailand, Cambodia) - 4,350 km; Pearl river source (shared with China [m]) - 2,200 km; Red river mouth (shared with China [s]) - 1,149 km note: [s] after country name indicates river source; [m] after country name indicates river mouth