The calculated distance (air line) between Monte Porzio Catone and Guidonia Montecelio is approximately 12 miles respectively 20 kilometers.
By car or train, the actual journey to Guidonia Montecelio is certainly longer, as only the direct route (as the crow flies) between Monte Porzio Catone and Guidonia Montecelio has been calculated here.
Air line (approximately)
20 kilometers
11 nautical miles