The patron saint of Guardiaregia is Saint Nicholas of Bari, celebrated on 9 May. The church dedicated to him was of medieval origin, but the powerful 1805 earthquake destroyed it, as the town, standing in a dominant position on the Matese, was among the settlements most damaged by the earthquake. It was rebuilt in Neoclassical style, with a three-nave basilica plan, a tripartite façade with three portals, and a compact tower bell tower with a spire.
The town lies at the foot of Monte Mutria, one of the highest peaks of the Matese massif, and is rich in watercourses, such as the Quirino torrent. Among the territory's other religious buildings is also the church of the Madonna della Neve.
