The calculated distance (air line) between Hamhŭng and Sŭngjibaegam is approximately 113 miles respectively 182 kilometers.
By car or train, the actual journey to Sŭngjibaegam is certainly longer, as only the direct route (as the crow flies) between Hamhŭng and Sŭngjibaegam has been calculated here.
Air line (approximately)
182 kilometers
98 nautical miles