The calculated distance (air line) between Chaeryŏng-ŭp and Sinanju is approximately 83 miles respectively 133 kilometers.
By car or train, the actual journey to Sinanju is certainly longer, as only the direct route (as the crow flies) between Chaeryŏng-ŭp and Sinanju has been calculated here.
Air line (approximately)
133 kilometers
72 nautical miles