The calculated distance (air line) between Phanom Sarakham and Chon Buri is approximately 36 miles respectively 58 kilometers.
By car or train, the actual journey to Chon Buri is certainly longer, as only the direct route (as the crow flies) between Phanom Sarakham and Chon Buri has been calculated here.
Air line (approximately)
58 kilometers
32 nautical miles