South Korea, country in East Asia. It occupies the southern portion of the Korean peninsula. The country is bordered by the Democratic People’s Republic of Korea (North Korea) to the north, the East Sea (Sea of Japan) to the east, the East China Sea to the south, and the Yellow Sea to the west; to the southeast it is separated from the Japanese island of Tsushima by the Korea Strait. South Korea makes up about 45 percent of the peninsula’s land area. The capital is Seoul (Sŏul).
South Korea faces North Korea across a demilitarized zone (DMZ) 2.5 miles (4 km) wide that was established by the terms of the 1953 armistice that ended fighting in the Korean War (1950–53). The DMZ, which runs for about 150 miles (240 km), constitutes the 1953 military cease-fire line and roughly follows latitude 38° N (the 38th parallel) from the mouth of the Han River on the west coast of the Korean peninsula to a little south of the North Korean town of Kosŏng on the east coast.
