Plaça d'Espanya station serves as the Barcelona terminus of the line, then continuing northwards to Martorell, where two main branches to Manresa and Igualada are formed.

It also includes several freight branches, accounting for a total line length of 138 kilometres (86 mi) and 41 passenger stations.

The section between Barcelona and Olesa de Montserrat is operated as a high-frequency commuter rail system known as Baix Llobregat Metro (Catalan: Metro del Baix Llobregat), with some services continuing northwards to Manresa and Igualada.

The Llobregat–Anoia Line originated from three formerly separate narrow gauge railway lines: Tranvía o Ferrocarril Económico de Manresa a Berga (opened in 1885), Ferrocarril Central Catalán (opened in 1893) and Camino de Hierro del Nordeste de España, built to quickly and cheaply give passenger and freight transportation to the rapidly industrialising Llobregat area.

In January 2017, the Catalan government approved a plan to extend the Llobregat–Anoia line from Plaça d'Espanya through the city as far as Gràcia station, also stopping at Hospital Clínic and Francesc Macià station, thereby linking with the Barcelona–Vallès Line, at an estimated cost of over €300 million.