The Diocese of Rennes is a Roman Catholic diocese located in the region of Brittany, France. It was established in the 3rd century and is part of the ecclesiastical province of Rennes. The diocese covers the city of Rennes and surrounding areas, serving a diverse population through various parishes and religious institutions. The diocese is known for its rich history and cultural heritage, including notable churches and religious sites. The Bishop of Rennes oversees the spiritual and administrative functions of the diocese, guiding the local Catholic community in faith and service.