The calculated distance (air line) between San Agustín Acasaguastlán and Retalhuleu is approximately 118 miles respectively 189 kilometers.
By car or train, the actual journey to Retalhuleu is certainly longer, as only the direct route (as the crow flies) between San Agustín Acasaguastlán and Retalhuleu has been calculated here.
Air line (approximately)
189 kilometers
102 nautical miles