Korea (Korean: 한국 Hanguk [hanɡuːk] or 조선 Joseon [tɕosʌn] – South and North Korea, respectively (cf. etymology)) is a territory of East Asia that was formerly unified under one state, but now divided into two separate states and a region in northeastern Asia. Located on the Korean Peninsula, it is bordered by China to the northwest, Russia to the northeast, and is separated from Japan to the east by the Korea Strait and the Sea of Japan (East Sea).

Korea was united until 1948, when it was split into South Korea and North Korea. South Korea, officially the Republic of Korea, is a free market, democratic and developed country, with memberships in the United Nations, WTO, OECD and G-20 major economies. North Korea, officially the Democratic People's Republic of Korea, is a socialist regime founded by Kim Il-sung and currently led by his son Kim Jong-il.

Archaeological and linguistic evidence suggest the origins of the Korean people were Altaic language-speaking people from south-central Siberia, who populated ancient Korea in successive waves from the Neolithic age to the Bronze Age. The adoption of the Chinese writing system ("Hanja" in Korean) in the 2nd century BC, and Buddhism in the 4th century AD, had profound effects on the Three Kingdoms of Korea.

During the latter part of the Joseon Dynasty, Korea's isolationist policy earned it the Western nickname the "Hermit Kingdom". By the late 19th century, the country became the object of the colonial designs of Japan. In 1910 Korea was annexed by Japan, becoming part of the Japanese Empire, and remained so until the end of World War II in August 1945.

In 1945, the Soviet Union and the United States agreed on the surrender and disarming of Japanese troops in Korea; the Soviet Union accepting the surrender of Japanese weaponry north of the 38th parallel and the United States taking the surrender south of it. This minor decision by allied armies soon became the basis for the division of Korea by the two superpowers, exacerbated by their inability to agree on the terms of Korean independence. The two Cold War rivals then established governments sympathetic to their own ideologies, leading to Korea's current division into two political entities: North Korea and South Korea. The ensuing conflict between the two was largely a proxy-war.