The calculated distance (air line) between Hwangju-ŭp and Haeju is approximately 44 miles respectively 70 kilometers.
By car or train, the actual journey to Haeju is certainly longer, as only the direct route (as the crow flies) between Hwangju-ŭp and Haeju has been calculated here.
Air line (approximately)
70 kilometers
38 nautical miles