The town is located between the mountain range of the Picentini mountains and the river Calore, the latter is fed by the different springs that arise precisely in the municipal territory.

Several groups of springs: Pollentina, Peschiera, Acqua del Prete and Bagno della Regina.

The above mentioned feed the aqueducts of the Alto Calore and the well-known Apulian Aqueduct.

The land is mixed cultivation: arable land, vineyards, and vegetables. The main agricultural product is the "Montella chestnut", in fact with the municipalities of Bagnoli Irpino and Montella is among the major producers in the area. The "Cassano apple", very similar to the annurca apple, is also common among Cassano Irpino, Montella and Volturara Irpina.

The origin of the name dates back to the Roman age and derives from the name of the "Gens Cassia" and from the suffix prediale -anus, which indicates a praedium Cassianum, that is a large estate or a rustic villa belonging to that family.

There are seven churches. The main ones are the Mother Church of San Bartolomeo Apostolo, Santa Maria delle Grazie, San Rocco, Santa Maria La Longa.

The castle probably built in the Lombard era as an isolated fortress to defend and control the territory, after a series of restorations, is now fully usable, used for events and administrative activities.

It underwent, in the following centuries, transformations and expansions and became the seat of the feudal lord, around it was formed the first nucleus of the medieval village that gave rise to the current town. The ancient names of alleys and squares of the medieval Cassano are still in use. Starting from 1445, when King Alfonso of Aragon sold to the noble Garcia I Cavaniglia the feuds of Montella, Bagnoli Irpino and Cassano Irpino, the castle took the name of Palazzo Baronale.