The calculated distance (air line) between Jablonec nad Nisou and Děčín is approximately 42 miles respectively 68 kilometers.
By car or train, the actual journey to Děčín is certainly longer, as only the direct route (as the crow flies) between Jablonec nad Nisou and Děčín has been calculated here.
Air line (approximately)
68 kilometers
36 nautical miles