The calculated distance (air line) between Huai Mek and Udon Thani is approximately 64 miles respectively 104 kilometers.
By car or train, the actual journey to Udon Thani is certainly longer, as only the direct route (as the crow flies) between Huai Mek and Udon Thani has been calculated here.
Air line (approximately)
104 kilometers
56 nautical miles