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