The calculated distance (air line) between Montemor-o-Novo and Rio de Mouro is approximately 61 miles respectively 98 kilometers.
By car or train, the actual journey to Rio de Mouro is certainly longer, as only the direct route (as the crow flies) between Montemor-o-Novo and Rio de Mouro has been calculated here.
Air line (approximately)
98 kilometers
53 nautical miles