Ŭnsan County is a kun (county) in South P'yŏngan province, North Korea.^[1]

The name Unsan is proposed to have been derived from either the Chinese character 银 or 隐, both read as "un" in Korean, referring to the possibility of silver being mined in a mine located in Sinchang, or 'hidden', as the area is surrounded by mountains, such as Hwasan. However, in historical records, only the word 殷 has been recorded as a name.^[2]

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.^[2]

In 1954, the original Unsan-up and Suwon-ri were merged and renamed to Sinchang-ri, while parts of Jinsan-ri and Sonam-ri became the new Unsan-up.^[2]

In 1974, several dongs were promoted to rodongjagu amongst a large scale reorganisation of districts, with some districts joining Sunchon.^[2]

In 1994, Sinpyong-ri was transferred to Pukchang County.^[2]

By the 1990s, Kubong-rodongjagu had been developed into a large mining town, with over 4600 residences and various services, such as hospitals, culture halls and schools.^[3]

Ŭnsan county is divided into 1 ŭp (town), 5 rodongjagu (workers' districts) and 16 ri (villages):

Ŭnsan County is served by the P'yŏngra and Ŭnsan lines of the Korean State Railway.

A trolleybuses existed in Kubong-rodongjagu, serving the Ryongdae Mine. This line had a stated length of 10-ri with 4 stops, connecting the workers' district to the entrance 2nd pit of Ryongdae Mine. Services run 24 hours a day, 7 days a week.^[3]