The calculated distance (air line) between Reguengos de Monsaraz and Barreiro is approximately 85 miles respectively 136 kilometers.
By car or train, the actual journey to Barreiro is certainly longer, as only the direct route (as the crow flies) between Reguengos de Monsaraz and Barreiro has been calculated here.
Air line (approximately)
136 kilometers
74 nautical miles