The calculated distance (air line) between T’ongch’ŏn-ŭp and Seoul is approximately 108 miles respectively 174 kilometers.
By car or train, the actual journey to Seoul is certainly longer, as only the direct route (as the crow flies) between T’ongch’ŏn-ŭp and Seoul has been calculated here.
Air line (approximately)
174 kilometers
94 nautical miles