The Military Demarcation Line, sometimes referred to as the Armistice Line, is the border between North Korea and South Korea. The Military Demarcation Line was established as the ceasefire line at the end of Korean War hostilities in 1953. The Military Demarcation Line runs over land; at sea, the two Koreas are divided by the Northern Limit Line.
This line is inside the DMZ, and runs near the 38th parallel, covering roughly 248 kilometers. United States and South Korea soldiers patrol this line along the South Korean side while (North) Korea People's Army patrol along the North Korean side. There have been frequent skirmishes along the line since the end of the Korean War.
In Korean, the line is called the Hyujeonseon, or "ceasefire line." It is also sometimes called the Gunsa Bungye-seon (군사분계선), which literally means "military demarcation line." However, in colloquial usage, the dividing line is more often called the Sampalseon (삼팔선, "38th parallel"), a name likely coined at the end of World War II, when it would have been an accurate description of the North-South border.
The line itself is marked off by a series of identical signs which are placed at intervals across the peninsula. The north facing side of the signs are written in Chosongul and Chinese, and in Hangul and English on the south facing side. The signs are aging and rusting.