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