The calculated distance (air line) between Twimoraet’ŏ and Namp’o is approximately 23 miles respectively 38 kilometers.
By car or train, the actual journey to Namp’o is certainly longer, as only the direct route (as the crow flies) between Twimoraet’ŏ and Namp’o has been calculated here.
Air line (approximately)
38 kilometers
20 nautical miles