[1] Established in 1923 through the merger of six smaller railways,[2] by the mid 1930s the Chosen Railway (Chōtetsu) had become the largest privately owned railway in colonial Korea, and had built an extensive network of 762 mm (30.0 in) narrow gauge rail lines in the Hwanghae region.

By the end of 1935, this Hwanghae Line network ran Sariwŏn—Samgang—Sugyo, Samgang—East Haeju—Haeju Port,[3] and Haeju—East Haeju—Tosŏng.

[4] On 10 May 1937, Chōtetsu opened a short (0.7 km (0.43 mi)) line from Tongp'o, located on the Haeju—Ch'wiya section (extended to Ongjin on 19 May[5]) of the Hwanghae Line network, to Chŏngdo to serve the Haeju Port.

After the end of the Pacific War and the subsequent partition of Korea, the Chŏngdo Line was located within the territory of the DPRK.

[8] A yellow background in the "Distance" box indicates that section of the line is not electrified.