The calculated distance (air line) between Bua Yai and Udon Thani is approximately 129 miles respectively 207 kilometers.
By car or train, the actual journey to Udon Thani is certainly longer, as only the direct route (as the crow flies) between Bua Yai and Udon Thani has been calculated here.
Air line (approximately)
207 kilometers
112 nautical miles