What geographical feature defined the division of combatants during the Korean War?

The 38th Parallel served as the primary geographical feature that divided North and South Korea before and during the Korean War. This line of latitude was significant because it was originally established as the boundary between the Soviet and American occupation zones following Japan's defeat in World War II. As tensions between the two superpowers rose, this division solidified into two separate governments, with North Korea (Democratic People's Republic of Korea) supported by the Soviet Union and later China, and South Korea (Republic of Korea) backed by the United States and other Western allies.

During the Korean War, which began in 1950 when North Korea invaded South Korea, the 38th Parallel became a critical front line. The conflict saw intense battles and shifting territorial control around this line, ultimately leading to a stalemate and the establishment of a Demilitarized Zone (DMZ) near the 38th Parallel after the armistice in 1953. This geographical marker not only represented a military and ideological division but also a symbol of the Cold War tensions that permeated the era.