The calculated distance (air line) between Unión de Reyes and Guanabacoa is approximately 54 miles respectively 86 kilometers.
By car or train, the actual journey to Guanabacoa is certainly longer, as only the direct route (as the crow flies) between Unión de Reyes and Guanabacoa has been calculated here.
Air line (approximately)
86 kilometers
47 nautical miles