[2] Historical records indicate that one of the earliest tribal states in Korea, known as Jinbeon, was located in the Hwanghae region.

[2] After Silla unified the three kingdoms, it became part of Bokjigun (瀑池郡) in 757 (16th year of King Gyeongdeok 's reign).

Then in 1018, during the ninth year of King Hyeonjong's reign over Goryeo, the county was established as one of the major administrative divisions in the kingdom's heartland.

It is difficult to reach Ongjin County because of its proximity to North Korea and its distance from South Korean areas.

The survivalist television series Squid Game created by Hwang Dong-hyuk for Netflix was filmed on Seongapdo island (part of Jawol-myeon) in 2020–2021.