The last-mentioned line also gives indirect connexion with the port of Coatzacoalcos, and the Mexican Central, via San Luis Potosi, with Tampico.
Of the principal ports on this coast, Matamoros, Tampico, Tuxpan, Coatzacoalcos and Frontera are on rivers, which are obstructed by bars.
Tampico and Coatzacoalcos, however, have been improved by breakwaters or jetties, and the deepening of the Channels across the bars, into safe and commodious harbours.
This line crosses the Isthmus of Tehuantepec from Coatzacoalcos (officially Puerto Mexico) on the Gulf coast to Salina Cruz on the Pacific coast, and has been under construction many years.
The larger ports for foreign trade are Vera Cruz, Tampico, Progreso, Carmen and Coatzacoalcos on the Gulf coast, and Guaymas, La Paz, Mazatlan, Manzanillo, San Blas, Acapulco and Salina Cruz on the Pacific coast.