It is also part of the European route E9, from Orléans (France) to Barcelona (Catalonia, Spain).

The road starts at Barcelona's Via Augusta and heads northbound crossing the Serra de Collserola mountain range, through the Vallvidrera tunnel, and then the comarques of Vallès Occidental, Bages and Berguedà.

The highway finishes at the connection with road N-260 at Puigcerdà, very close to the French border.

This highway, along with C-17, is a main south–north link in Catalonia, since it connects Barcelona with several significant inland cities and towns such as Terrassa, Manresa, Berga, and Puigcerdà.

It is also the straightest and quickest way from the Cerdanya comarca and from Andorra to the centre, south, and east of Catalonia.