On the top of a hill, the town is easily identifiable thanks to its castle that dominates the valley. In the Roman era it was an important stop on the military road, the via Fulvia, from Valenza and Asti to Pollentia.
In 1014, an imperial diploma gave Castellinaldo to the abbey of S.Benigno in Fruttuaria. It ws then called “castrum Aynaldi”, because it was a feud of the Ainaldi family. That’s where the town had its name from. The faud was then given to the Malabaila family, then to the Damiano del Carretto, the marquis Faussone di Clavesana and to the count Ripa di Meana, its present owner.
The high part of the town is made unique by the many colors of the houses, recently restored, that create an ancient and picturesque atmosphere. Interesting is the late-Romanesque little church, dedicated to S. Servazio, built on the top of the homonymous hill.