The calculated distance (air line) between T’ongch’ŏn-ŭp and Pyongyang is approximately 115 miles respectively 185 kilometers.
By car or train, the actual journey to Pyongyang is certainly longer, as only the direct route (as the crow flies) between T’ongch’ŏn-ŭp and Pyongyang has been calculated here.
Air line (approximately)
185 kilometers
100 nautical miles