The calculated distance (air line) between Al Maḩmūdīyah and Damietta is approximately 78 miles respectively 125 kilometers.
By car or train, the actual journey to Damietta is certainly longer, as only the direct route (as the crow flies) between Al Maḩmūdīyah and Damietta has been calculated here.
Air line (approximately)
125 kilometers
68 nautical miles