The calculated distance (air line) between Mueang Nonthaburi and Suphan Buri is approximately 50 miles respectively 80 kilometers.
By car or train, the actual journey to Suphan Buri is certainly longer, as only the direct route (as the crow flies) between Mueang Nonthaburi and Suphan Buri has been calculated here.
Air line (approximately)
80 kilometers
43 nautical miles