The calculated distance (air line) between Yehud-Monosson and Ashdod is approximately 21 miles respectively 34 kilometers.
By car or train, the actual journey to Ashdod is certainly longer, as only the direct route (as the crow flies) between Yehud-Monosson and Ashdod has been calculated here.
Air line (approximately)
34 kilometers
18 nautical miles