The calculated distance (air line) between Jabālyā and Dayr al Balaḩ is approximately 11 miles respectively 18 kilometers.
By car or train, the actual journey to Dayr al Balaḩ is certainly longer, as only the direct route (as the crow flies) between Jabālyā and Dayr al Balaḩ has been calculated here.
Air line (approximately)
18 kilometers
9 nautical miles