South Korea, country in northeastern Asia that occupies the southern portion of the Korea Peninsula; officially known as the Republic of Korea. South Korea is bounded on the north by North Korea; on the east by the East Sea; on the southeast and south by the Korea Strait, which separates it from Japan; and on the west by the Yellow Sea. The capital and largest city is Seoul.
The nation of South Korea was established in 1948 following the post-World War II partitioning of Korea between the occupying forces of the United States in the south and the former Union of Soviet Socialist Republics (USSR) in the north. After the Korean War (1950-1953), South Korea rose from devastation to become one of the world's largest economies in the 1990s.