The calculated distance (air line) between Dayr Ḩāfir and Al Mayādīn is approximately 173 miles respectively 278 kilometers.
By car or train, the actual journey to Al Mayādīn is certainly longer, as only the direct route (as the crow flies) between Dayr Ḩāfir and Al Mayādīn has been calculated here.
Air line (approximately)
278 kilometers
150 nautical miles