Hungdok-gun, the predecessor to the current administrative division, was formed in the early
Goguryeo period from
Sunchon-gun. This later became Unju in 983 and subsequently Unsan-hyon in 1278. In 1414, after the establishment of the
Joseon, it was briefly absorbed into Chasan-gun, then reestablished in 1415. In 1895, the
myon was reorganised into a gun and subsequently was changed into a
hyon in 1896. It was again absorbed into Sunchon-gun in 1907 and reestablished in 1952. ==Administrative divisions==