The patron saint of Parrano is Saint Blaise, celebrated on 3 February. The castle overlooking the settlement, the core around which the village grew, was built in a strategic position on Roman ruins and was first mentioned in a document from 1118, through which the bishop of Orvieto, Guglielmo, invested Bernardo di Bulgarello with the title of count and feudal privileges over Parrano. Inside it still holds the chapel of San Biagio, which once opened directly into the town's church; the building also preserves two tall square battlemented towers and a hanging garden.
At the base of the outcrop on which Parrano stands winds a labyrinth of karst caves known as the Tane del Diavolo, where finds dating back to the Bronze Age have been discovered: hut floors, ceramics, small terracotta vessels, necklaces and fragments of animal bones.
