The name probably derives from the large presence and cultivation of chestnut trees in the area. It is a municipality located in the province of Asti in the Monferrato Basso, equidistant from Alessandria, Asti and Casale Monferrato, on a hill from which it is possible to admire the Alps in the days when the mist is not present. The village, devoted mainly to agriculture, features several old buildings, including houses and fine churches of the XV century. It is famous worldwide for its wine Ruchè, produced with the grapes of a vine of ancient origins, which grows only in this area..
The via Fulvia and the specific names of several districts in the area, all Roman anthroponyms (personal names), undoubtedly attest to the presence of Roman settlements in the territory. During the V-VI centuries A.D., after the fall of the Roman Empire, the area was inhabited by the Lombards and the Franks, that, over the following centuries, submitted several Saracen invasions. During the medieval period, Castagnole was at the center of a series of disagreements between the Marquis of Monferrato and the rulers of the town of Asti, both interested in its acquisition. The treaties that followed allowed Asti to establish an agreement and to build a castle. At the end of the XIII century, the town rebelled against the Marquis of Monferrato and forced its Lords to swear allegiance, but after a period of conflicts, Castagnole returned to the Marquis of Monferrato. In the early XIV century the Marquis of Saluzzo ceded the fief in pledge to Charles of Provence, while in the following centuries it became part of the domain of the Palaeologo Family.

Not to miss:
- the Parish Church of San Martino, built in the XVIII century on the remains of an older one. It features a three nave plan with side chapels in Baroque style. Inside it preserves three masterpieces of the artist Moncalvo, a wooden statue of Santa Margherita, a wooden sculpture depicting the Last Supper and two fonts of the Renaissance period;
- the Confraternity of the Annunciation in Baroque style, located opposite to the church of San Martino, features a splendid engraved portal;
- the XVII century Church of San Rocco, which contains a valuable statue of the saint;
- the remains of the ancient castle and its fortified walls, which in some points is still intact, with XIV century arches, massive walls and a watch tower. Interesting is the façade facing South, built in brick with lancet windows, and the east side with Gothic windows and portals;
- the interesting and ancient buildings featuring various architectural styles. The old cellars built in the tuff stone.