The calculated distance (air line) between Prey Veng and Smach Mean Chey is approximately 155 miles respectively 250 kilometers.
By car or train, the actual journey to Smach Mean Chey is certainly longer, as only the direct route (as the crow flies) between Prey Veng and Smach Mean Chey has been calculated here.
Air line (approximately)
250 kilometers
135 nautical miles