The calculated distance (air line) between Nong Bua Lamphu and Udon Thani is approximately 27 miles respectively 44 kilometers.
By car or train, the actual journey to Udon Thani is certainly longer, as only the direct route (as the crow flies) between Nong Bua Lamphu and Udon Thani has been calculated here.
Air line (approximately)
44 kilometers
24 nautical miles