The calculated distance (air line) between Yŏnan-ŭp and Hwangju-ŭp is approximately 57 miles respectively 91 kilometers.
By car or train, the actual journey to Hwangju-ŭp is certainly longer, as only the direct route (as the crow flies) between Yŏnan-ŭp and Hwangju-ŭp has been calculated here.
Air line (approximately)
91 kilometers
49 nautical miles