In a region that is known to be of very ancient origin, it is said that there were once two castles here, one by the name of Aguiar de Sousa and the other known as the castle of Pena. When the Moors occupied this region, they tried to invade the latter castle, but did not succeed because it was defended so heroically. This is why it was considered "loyal" (fiel), so that it became known as the castle of Penafiel, a name which then spread to the rest of the area.
Standing at the heart of a region of granite and vinho verde, Penafiel is also the centre for various lively and popular religious festivities held around the time of Corpus Christi.
In the surrounding region, attention is drawn to the many Romanesque churches, such as the monastery of São Salvador at Paço de Sousa and the churches of São Miguel at Eja and São Salvador at Gandra.