mately 1,500 miles of irregular coastline on the Tonkin Gulf and the South China Sea complete the enclosure of its 66,000-square mile area.
South Vietnam is divided into four relatively distinct physiographic regions-the Mekong Delta, the coastal plain, the Annamite Mountains, and the forested plain. The Mekong Delta, an extensive and fertile lowland centered on the Mekong River, covers roughly the southern quarter of the country. This region is essentially a marshy flat land well suited for rice growing and is recognized as one of Asia's richest agricultural areas. South Vietnam's second physiographic region, the coastal plain, is similar to the Mekong Delta in that it is predominantly flat and generally well suited for rice growing. Properly known as the coastal lowland, this region extends from the country's northern border to the Mekong Delta. Its width is never constant, being defined on the west by the rugged Annamite Mountains-the region which dominates the northern two thirds of South Vietnam. The jungle-covered mountains, whose highest elevations measure over 8,000 feet, stand in sharp contrast to the low and flat coastal plain. The eastern slopes of the mountains normally rise from the lowlands at a distance of five or 10 miles from the sea. At several points along the coast, however, the emerald mountains crowd to the water's edge, dividing the coastal plain into compartments and creating a seascape breathtaking in its beauty. At other locations the mountain chain recedes from the coast, allowing the lowlands to extend inland as far as 40 miles. An extensive upland plateau sprawls over the central portion of South Vietnam's mountain region.
This important subrcgion, known as the Central Highlands, possesses relatively fertile soil and has great potential for agricultural development. The highest elevations in the Annamite chain are recorded south of the Central Highlands. From heights of 6,000 to 7,000 feet, the mountains dissolve southward into the forested plain, a hilly transition zone which forms a strip between the Mekong lowlands and the southernmost mountains.
South Vietnam lies entirely below the Tropic of Cancer. Its climate is best described as hot and humid. Because the country is situated within Southeast Asia's twin tropical monsoon belt, it experiences two distinct rainy seasons. The south-west (or summer) monsoon settles over the Mekong
Delta and the southern part of the country in mid-May and lasts until early October. In the northern reaches, the northeast (or winter) monsoon season begins in November and continues through most of March. Unlike the rainy season in the south, fog, wind, and noticeably lower temperatures characterize the wet season in the north. While the reversed monsoon seasons provide an abundance of water for rice growing throughout the Mekong Delta and most of the long coastal plain, rainfall is not distributed uniformly. Parts of the central coast record only about 28 inches of annual precipitation. In contrast, other areas along the northern coast receive as much as 126 inches of rain during the course of a year. Even worse, a percentage of this rainfall can be expected to occur as a result of typhoons. The tropical storms usually lash the Annamese coast between July and November. Almost always they cause extensive flooding along normally sluggish rivers which dissect the coastal plain.
Slightly over 16 million people currently inhabit South Vietnam. Of these, over 13 million are ethnic Vietnamese. Primarily rice farmers and fishermen, the Vietnamese have tended to compress themselves into the country's most productive agricultural areas-the Mekong Delta and the coastal plain. Chinese, numbering around one million, form South Vietnam's largest ethnic minority. Concentrated for the most part in the major cities, the Chinese traditionally have played a leading role in Vietnam's commerce. About 700,000 Montagnard tribesmen, scattered across the upland plateau and the rugged northern mountains, constitute South Vietnam's second largest minority. Some 400,000 Khmers, closely akin to the dominant population of Cambodia, inhabit the lowlands along the Cambodian border. Roughly 35,000 Chams, remnants of a once powerful kingdom that blocked the southern migration of the Vietnamese until the late 1400s, form the country's smallest and least influential ethnic minority. The Chams, whose ancestors once controlled most of the central and southern Annamese coast, are confined to a few small villages on the central coast near Phan Rang.
Page 6 (The Advisory & Combat Assistance Era: 1954-1964)