The tunnel, with a length of 5,026 m (16,490 ft), is part of the C-16 highway and E-9, running under the Serra de Moixeró mountain range in the Pre-Pyrenees.

The southern entrance, at an altitude of 1,175 m (3,855 ft), is located in the settlement of Gréixer, part of the municipality of Guardiola de Berguedà, in the watershed of the Llobregat river.

In 1973 the company Promociones Pirinaicas, S.A. was granted a license by the government to build, maintain, and manage a tunnel through the Serra del Cadí.

This work completed a segment of the C-1411 highway, intended to run from Manresa to Bellver de Cerdanya.

[4] Since then, this segment has been added to the C-16 highway, "Eix del Llobregat", which runs from Barcelona to Puigcerdà, and thence to Orleans as part of European route E9.