The calculated distance (air line) between Sihanoukville and Smach Mean Chey is approximately 73 miles respectively 117 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 Sihanoukville and Smach Mean Chey has been calculated here.
Air line (approximately)
117 kilometers
63 nautical miles