The Diocese of Nueva Segovia is a Roman Catholic diocese located in the Philippines, specifically in the province of Ilocos Sur. Established in 1583, it is one of the oldest dioceses in the country. The diocese is part of the Ecclesiastical Province of Nueva Segovia and serves a diverse population through various parishes and missions. The diocese's cathedral, known as the Cathedral of the Immaculate Conception, is situated in the city of Vigan. It plays a central role in the spiritual life of the community and hosts important liturgical events. The diocese is dedicated to promoting the Catholic faith and providing pastoral care to its members.