Some fifty million years ago, the area now known as Berango was covered by the sea, about a thousand metres underwater. That is what the geological maps studied and the fossils found in the territory tell us .

We also know that 40,000 years ago the pre-historical man used to live in the coastal fringe that runs from the Plentzia estuary to the Bilbao estuary, in the very place where our municipality is located.

He stayed there during all the pre-historical period, as we can see from the findings, mainly the flint tools that he used, but also the funerary tumuli discovered in Munarrikolanda, the place where the dead used to be buried some 3,000 or 4,000 years ago.

Before our Era, our predecessors in what is now Berango were thought to belong to a Basque tribe called the Caristians, due to the fact that, according to Estrabón, they were settled in a wide area, which was delimited by the municipalities now known as Deba, Getxo, Trebiño and Miranda.

Most of the lands occupied by the Caristians were later called Bizkai, which is already mentioned in certain documents dating back to around 900.