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.
As a result of several land reform measures, Vietnam has become a major exporter of agricultural products. It is now the world's largest producer of cashew nuts, with a one-third global share; the largest producer of black pepper, accounting for one-third of the world's market; and the second-largest rice exporter in the world after Thailand since the 1990s. Subsequently, Vietnam is also the world's second largest exporter of coffee. The country has the highest proportion of land use for permanent crops together with other states in the Greater Mekong Subregion. Other primary exports include tea, rubber and fishery products. Agriculture's share of Vietnam's GDP has fallen in recent decades, declining from 42% in 1989 to 20% in 2006 as production in other sectors of the economy has risen.