Located in the historic center of Macchia d’Isernia, the Church of Saint Nicholas Bishop of Bari is the main religious building of the village and has been its spiritual heart for centuries. It is documented as early as 1182, when Pope Lucius III refers to it in a papal bull as plebem S. Nicolai in Maccla, confirming its medieval origin.
The church has a longitudinal single-nave layout, with irregular stone courses on the exterior walls. A Baroque stone portal from the 18th century, with a broken curved tympanum, is accessed via an external staircase. Beside the façade stands a medieval bell tower, divided into three tiers by decorated stone cornices, featuring slit openings and finely worked stone corners.
The interior follows the Baroque style with a single nave and six side altars—two on the right and four on the left. A life-sized statue of Saint Nicholas is carried through the village during the annual procession on his feast day, and on other major religious celebrations such as the Holy Trinity, Corpus Christi, the Assumption, Saint Rocco, Saint Blaise, and Our Lady of Loreto.
The church was extensively restored in 1780 thanks to the support of the d’Alena barons and Bishop Umbriatico of Isernia. It was formally rededicated to Saint Nicholas of Bari, honoring Nicola d’Alena, the first feudal lord of Macchia from the noble house of d’Alena.