The calculated distance (air line) between Kampong Thom and Smach Mean Chey is approximately 149 miles respectively 239 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 Kampong Thom and Smach Mean Chey has been calculated here.
Air line (approximately)
239 kilometers
129 nautical miles