The patron saint of Isnello is Saint Nicholas of Bari, bishop of Myra, celebrated on 6 December in the mother church dedicated to him: of ancient foundation, it now appears in the form it took between the late 16th and early 17th centuries.
The town also preserves the church of San Michele Arcangelo, with frescoes datable to the 14th-15th centuries, the wooden organ, pulpit and tabernacle by the Polizzi sculptor Pietro Bencivinni, the 16th-century statue of Saint Michael, a 1627 wooden crucifix, and stucco decorations by the Messina brothers and Gaspare l'Abbate, from the 17th century. On a ridge overlooking the town stand the ruins of the Norman castle, now owned by the Virga family: in September 1377 the barony of Isnello was sold to Francesco II Ventimiglia, count of Geraci, whose successor Antonio lost the rights to it for treason. On 1 February 1397 King Martin granted the barony to Abbo Filangeri, alcaide of Cefalù, who later ceded it to obtain the County of San Marco.
