The calculated distance (air line) between Siem Reap and Tbeng Meanchey is approximately 81 miles respectively 131 kilometers.
By car or train, the actual journey to Tbeng Meanchey is certainly longer, as only the direct route (as the crow flies) between Siem Reap and Tbeng Meanchey has been calculated here.
Air line (approximately)
131 kilometers
71 nautical miles