The calculated distance (air line) between Siem Reab and Kampong Cham is approximately 58 miles respectively 93 kilometers.
By car or train, the actual journey to Kampong Cham is certainly longer, as only the direct route (as the crow flies) between Siem Reab and Kampong Cham has been calculated here.
Air line (approximately)
93 kilometers
50 nautical miles