During the kingdom of Silla, the region formed the subdivision of Haego County (海皐郡, haegogun).

Other names later during the Goryeo era included Yeongeung prefecture (永膺縣),·Bokju (復州),·Seokju (碩州), and Onjumok (溫州牧).In 1310, Onjumok was degraded to a lower subdivision called a bu called Yonanbu (溫州府).In 1413 it became a Yonan dohobu and became part of Hwanghae Province instead of Gyeonggi Province.

[2] After the liberation of Korea, the region was briefly under the occupation zone of the Americans in the South of the Korean peninsula, then forming Yeonbaek County under Gyeonggi province.

[5] Yŏmjŏl-lodongjagu (염전로동자구,鹽田勞動者區) is a worker's district located on the southern coast of the county, which was named as such for its Salt evaporation ponds.

[7] Ahyŏl-li (아현리,雅峴里) is formed from merging part of Uihyolli and Takyongri and its name added the a(雅) meaning beautiful.

[12] Ch'angdŏng-ri (창덕리,氅德里) is named as such because of a story that Seonbis have showcased their De(德) while wearing a Changyi(氅衣).

[14] Ch'ŏnt'ae-ri (천태리,天台里) was named after the term Chontae, meaning high mountains.

[16] Haewŏl-li (해월리,海月里) was named after Mount Haewol.The place has a Walnut forest that was formed after the Korean War.

[23] Pongdŏng-ri (봉덕리,鳳悳里) was named after Pong of Pongdoksa temple and Dok of Doksan.

[35] Tonam-ri (도남리,桃南里) is a ri that was named as such because of the former subdivision Tosungri and the fact that it is at the south of Pyongsan County.

[36] Rodong sinmun and KCNA reported on the story of the 12th work team from Tonamri regarding the agricultural production achievements of the region at the collective farm.

[7] The region currently hosts the North Korean propaganda Mosaic mural "Always with the road for the people(언제나 인민을 위한 길에 함께 계시며)" depicting on the spot guidance.