The town's name has Roman origins, but the exact source is uncertain: the most accepted theory proposes that it derives from a person's propoer name "Aucius. It is a municipality in the province of Alexandria, famous for the extraction and processing of limestone, which since the XVII century and also in more recent times has given impetus to a flourishing industry. The town is perches on a hill and is protected by the castle, which overlooks the nearby parish church.
The town was mentioned for the first time in a document dating from the period between the IX and X centuries. Around the year 1000 Ozzano, together with the entire district of Casale, was donated by Emperor Otto III to the Bishop of Vercelli. During the XII century, Federico Barbarossa assigned the town to the Marquis Guglielmo V of the Family of the Aleramici. During this period began the fortification of the village, that ended in the XIV century. At the death of the last heir of the Aleramici, the territory was ceded to the Paleologi. After the period of regency of Otto of Brunswick, the town was assigned as a fief to Columbo Teodonimo and then to the Prince of Thessaly. In the first half of the XVI century it was sold to Mercurino Alborio of Gattinara. Under the rule of the Gonzaga, Ozzano suffered a difficult period because of the high taxes, and if the XVI century was not a happy one, the XVII century was even worse, due to the continuous attacks and sacking by the Spanish, the French, the Savoy and the Lanzichenecchi, which seriously marked the local history. At the end of the XVIII the town belonged to the Cocconato Family of Montiglio, until it finally passed to the Kingdom of Sardinia.

Not to miss:

- the Parish of St. Salvatore, which is located within the walls of the castle. Although it is not possible to determine the exact date of its construction, the oldest parts date back to the XIV century. The building is in Romanesque-Gothic style with Renaissance and Baroque elements, a result of several renovations and modifications over the centuries. The façade is in brickwork with two single arched windows and five pinnacles, the wooden portal in Baroque style is marked by an architrave surmounted by a small gable. It features a rectangular plan with three naves and a polygonal apse. The Bell tower has a square shape and is decorated with Romanesque belfry and characterized by the presence of four mullioned windows. The churchyard features river stones of different colors that make up a series of geometric patterns. It is decorated inside with a series of frescoes realized between the XV and the XIX centuries, and an extremely valuable Baroque altar;
- the Church of St. John the Baptist;
- the Castle, built between year 1000 and 1100, it is situated on the hill, overlooking the town with its outer walls. It is in Gothic style and features frescoes and paintings by Pier Francesco Guala, an XVIII century roof garden and a fine chapel