The calculated distance (air line) between Al Musayyib and Ḩadīthah is approximately 145 miles respectively 233 kilometers.
By car or train, the actual journey to Ḩadīthah is certainly longer, as only the direct route (as the crow flies) between Al Musayyib and Ḩadīthah has been calculated here.
Air line (approximately)
233 kilometers
126 nautical miles