The calculated distance (air line) between Ch’ŏsal-li and Hŭngnam is approximately 117 miles respectively 188 kilometers.
By car or train, the actual journey to Hŭngnam is certainly longer, as only the direct route (as the crow flies) between Ch’ŏsal-li and Hŭngnam has been calculated here.
Air line (approximately)
188 kilometers
102 nautical miles