The calculated distance (air line) between San Martín Cuautlalpan and Tlalnepantla is approximately 30 miles respectively 48 kilometers.
By car or train, the actual journey to Tlalnepantla is certainly longer, as only the direct route (as the crow flies) between San Martín Cuautlalpan and Tlalnepantla has been calculated here.
Air line (approximately)
48 kilometers
26 nautical miles