The calculated distance (air line) between San Francisco Zapotitlán and Retalhuleu is approximately 11 miles respectively 18 kilometers.
By car or train, the actual journey to Retalhuleu is certainly longer, as only the direct route (as the crow flies) between San Francisco Zapotitlán and Retalhuleu has been calculated here.
Air line (approximately)
18 kilometers
10 nautical miles