Line C (Buenos Aires Underground)

Line C of the Buenos Aires Underground, that runs from Retiro to Constitución terminus, opened on 9 November 1934, and it has a length of 4.3 km (2.7 mi). It runs under Lima Sur, Bernardo de Irigoyen, Carlos Pellegrini, Esmeralda, la Plaza San Martín and Avenida Ramos Mejia streets. It not only connects to every other line on the system (with the exception of Line H, which it is planned will be connected at a later date), but its termini at Retiro and Constitución also connect it to some of the most important commuter rail networks in Buenos Aires, such as the Mitre and Roca lines and also long-distance passenger services. It is thus an important artery in Buenos Aires' transport system. At the same time, it is also the shortest line in both terms of length and number of stations.

It was the third line of the network to provide rail services to the public, after Line A and Line B. Up until 2007 with the opening of line H, it was the only line in the system providing a north–south service.