三八线
In 1945 Gangwon-do (along with the rest of Korea) was divided by the 38th parallel north in 1945 into American and Soviet zones of occupation in the south and north respectively, which led to Wonsan joining the province's northern half in 1946 to serve as its administrative center. In 1948, the southern half of the province became part of the new Republic of Korea. As a result of the Korean War of 1953, the boundary between the South and North Korean portions of the province was shifted northward to the Military Demarcation Line.