The calculated distance (air line) between Sŭngjibaegam and Sŏnbong is approximately 112 miles respectively 180 kilometers.
By car or train, the actual journey to Sŏnbong is certainly longer, as only the direct route (as the crow flies) between Sŭngjibaegam and Sŏnbong has been calculated here.
Air line (approximately)
180 kilometers
97 nautical miles