The calculated distance (air line) between Sŭngjibaegam and Hongwŏn is approximately 95 miles respectively 153 kilometers.
By car or train, the actual journey to Hongwŏn is certainly longer, as only the direct route (as the crow flies) between Sŭngjibaegam and Hongwŏn has been calculated here.
Air line (approximately)
153 kilometers
83 nautical miles