Demilitarised zone (DMZ), region on the Korean peninsula that demarcates North Korea from South Korea. The demilitarised zone (DMZ) incorporates territory on both sides of the ceasefire line as it existed at the end of the Korean War (1950–53) and was created by pulling back the respective forces 1.2 miles (2 km) along each side of the line. It runs for about 150 miles (240 km) across the peninsula, from the mouth of the Han River on the west coast to a little south of the North Korean town of Kosong on the east coast.