The calculated distance (air line) between Incheon and Yangp'yŏng is approximately 43 miles respectively 69 kilometers.
By car or train, the actual journey to Yangp'yŏng is certainly longer, as only the direct route (as the crow flies) between Incheon and Yangp'yŏng has been calculated here.
Air line (approximately)
69 kilometers
37 nautical miles