Geography

South Korea occupies the southern portion of the Korean Peninsula, which extends some 1,100 km (680 miles) from the Asian mainland. Being on a peninsula, the only country with a land border is North Korea to the north with 238 km of border running along the DMZ. South Korea is mostly surrounded by water and has 2,413 km of coast line along three seas. To the west is the Yellow Sea, to the south is the East China Sea, and to the east is the Sea of Japan (East Sea). Its southern tip lies on the Korea Strait and the East China Sea.

The country's total area is 99,538 square kilometres, making it just slightly larger than Portugal.

Topography and Drainage

Early European visitors to Korea remarked that the land resembled 'a sea in a heavy gale' because of the large number of successive mountain ranges that crisscross the peninsula. The tallest mountains are in North Korea. The tallest mountain in South Korea is Hallasan (1,950 metres), which is the cone of a volcanic formation constituting Jeju Island. There are three major mountain ranges within South Korea: the Taebaek Mountains, and Sobaek ranges, and the Jiri Massif.

Unlike Japan or the northern provinces of China, the Korean Peninsula is geologically stable. There are no active volcanoes and there have been no strong earthquakes. Historical records, however, describe volcanic activity on Mount Halla during the Goryeo Dynasty (918-1392 AD).

The Nakdong is South Korea's longest river (521 kilometres). The Han River, which flows through Seoul, is 514 kilometres long, and the Geum River is 401 kilometres long. Other major rivers include the Imjin, which flows through both North Korea and South Korea and forms an estuary with the Han River; the Bukhan, a tributary of the Han that also flows out of North Korea; and the Somjin. The major rivers flow north to south or east to west and empty into the Yellow Sea or the Korea Strait. They tend to be broad and shallow and to have wide seasonal variations in water flow.

South Korea has no extensive plains; its lowlands are the product of mountain erosion. Approximately 30% of the area of South Korea consists of lowlands, with the rest consisting of uplands and mountains. The great majority of the lowland area lies along the coasts, particularly the west coast, and along the major rivers. The most important lowlands are the Han River plain around Seoul, the Byeongtaek coastal plain southwest of Seoul, the Geum River basin, the Nakdong River basin, and the Yeongsan and the Honam plains in the southwest. A narrow littoral plain extends along the east coast.

Over the centuries, Korea's inhabitants have cut down most of the ancient Korean forests, with the exception of a few remote, mountainous areas. The disappearance of the forests has been a major cause of soil erosion and flooding. Because of successful reforestation programs and the declining use of firewood as a source of energy since the 1960s, most of South Korea's hills in the 1980s were amply covered with foliage.

Land Area and Borders

The Korean Peninsula extends for about 1,000 kilometres southward from the northeast part of the Asian continental landmass. The west coast of the peninsula is bordered by the Korea Bay to the north and the Yellow Sea to the south; the east coast is bordered by the Sea of Japan. The Japanese islands of Honshu and Kyushu are located some 200 kilometres to the southeast across the Korea Strait; the Shandong Peninsula of China lies 190 kilometres to the west. Some 3,579 islands lie adjacent to the peninsula, most of them found along the south and west coasts.

The largest island, Jeju, lies off the southwest corner of the peninsula and has a land area of 1,825 square kilometres. Other important islands include Ulleung in the Sea of Japan (East Sea) and Ganghwa Island at the mouth of the Han River. Although the eastern coastline of South Korea is generally unindented, the southern and western coasts are jagged and irregular. The difference is caused by the fact that the eastern coast is gradually rising, while the southern and western coasts are subsiding.

The northern land border of the Korean Peninsula is formed by the Yalu and Tumen rivers, which separate Korea from the provinces of Jilin and Liaoning in China. The original border between the two Korean states was the thirty-eighth parallel of latitude. After the Korean War, the Korean Demilitarized Zone (DMZ) formed the boundary between the two. The DMZ is a heavily guarded, 4,000-metre-wide strip of land that runs along the line of cease-fire, the Demarcation Line, from the east to the west coasts for a distance of 241 kilometres (238 kilometres of that line form the land boundary with North Korea).