List of ambassadors of the United States to South Korea
At the end of World War II, American forces accepted Imperial Japan's surrender in southern Korea, and Soviet forces accepted the surrender of the Japanese in northern Korea. Talks to agree upon a unity government for Korea failed and in 1948, two separate Korean states were created: the Republic of Korea (South Korea) and the Democratic People's Republic of Korea (North Korea). The United States established diplomatic relations with the new South Korean government, but did not recognize North Korea. Other countries, like the Soviet Union, recognized the Pyongyang government in North Korea, but did not initially establish relations with the South Korean government in Seoul.
38th parallel north
Japan had occupied the Korean peninsula between 1910 and 1945. When Japan surrendered in August 1945, the 38th parallel was established as the boundary between Soviet and American occupation zones. This parallel divided the Korean peninsula roughly in the middle. In 1948, this parallel became the boundary between the Democratic People's Republic of Korea (North Korea) and the Republic of Korea (South Korea), both of which claim to be the government of the whole of Korea. On 25 June 1950, after a series of cross-border raids and gunfire from both the Northern and the Southern sides, the North Korean Army crossed the parallel and invaded South Korea. This sparked a United Nations resolution against the aggression and the Korean War, with United Nations troops (mostly Americans) helping to defend South Korea.