St Joseph Cathedral on Main Street is the seat of the Roman Catholic Diocese of Baton Rouge, built in the 1850s in a Gothic Revival style and substantially renovated in the 20th century. The interior is notable for its stained glass windows and the high vaulted ceiling.
The cathedral occupies an important place in Baton Rouge's civic history — Baton Rouge has been predominantly Catholic since the French colonial period, and the diocese predates Louisiana statehood. The building sits in the heart of the downtown historic district, a short walk from the river and the capitol area, and is generally open to visitors outside of service times.