South Korea, officially the Republic of Korea, is a country located in East Asia, in the southern half of the Korean Peninsula. To the north, it is bordered by North Korea, with which it formed a single nation until 1948.

 In the 1990s, South Korea became one of the world's largest economies. In 1996 South Korea joined the OECD. Although the nation suffered severe economic hardship during the Asian financial crisis, South Korea today is a fully functioning modern democracy and one of Asia’s most affluent nations.

 A potential Korean reunification has remained a prominent topic; no peace treaty has yet been signed with the North. In June 2000, a historic first North-South summit took place, part of the South's continuing Sunshine Policy of engagement. Since then, regular contacts have led to a cautious thaw.

 Korea forms a peninsula that extends some 1,100 km from the Asian mainland, flanked by the Yellow Sea (West Sea) and the Sea of  Japan (East Sea), and terminated by the Korea Strait and the East China Sea to the south. The southern landscape consists of partially forested mountain ranges to the east, separated by deep, narrow valleys. Densely populated and cultivated coastal plains are found in the west and south. About 3,000 islands, most of which are small and uninhabited, lie off the western and southern coasts. The total area of South Korea is 99,268 km².

 South Korea is a mountainous country. Lowlands, located primarily in the west and southeast, constitute only 30 percent of the total land area. South Korea can be divided into three general regions: an eastern region of high mountain ranges and narrow coastal plains; a western region of broad coastal plains, river basins, and rolling hills; and a southern region, where a maze of mountains and valleys in the west contrasts with the broad basin of the Nakdong River in the southeast.