The Armistice Line at the end of the Korean War left Ongjin County in North Korea.

The Five West Sea Islands were put under Ongjin County of South Korea since the Armistice.

a Yonghodo (용호도) sits in the entrance to Kangryŏng Bay, Ch'angrindo (창린도) is outside the entrance to Ongjin Bay, and Kirindo (기린도) lies south of the western end of the Ongjin Peninsula.

Ongjin county is divided into 1 ŭp (town), 3 rodongjagu (workers' districts) and 24 ri (villages) Rice is the major crop.

The nearby meeting of warm and cold currents make this a centre of the fishing industry.