The calculated distance (air line) between Uiju and Yonggang-ŭp is approximately 104 miles respectively 168 kilometers.
By car or train, the actual journey to Yonggang-ŭp is certainly longer, as only the direct route (as the crow flies) between Uiju and Yonggang-ŭp has been calculated here.
Air line (approximately)
168 kilometers
91 nautical miles