Jackson Square, also known as Place d'Armes, is a historic park in the French Quarter of New Orleans, Louisiana. On the opposite side of the square are three 18th‑century historic buildings which were the city's heart in the colonial era. The center of the three is St. Louis Cathedral. The cathedral was designated a minor Basilica by Pope Paul VI. To its left is the Cabildo, the old city hall, now a museum, where the finalization of the Louisiana Purchase was signed. To the Cathedral's right is the Presbytère, built to match the Cabildo. The Presbytère originally housed the city's Roman Catholic priests and authorities; it was then turned into a courthouse at the start of the 19th century, and in the 20th century became a museum. Saint Louis Cathedral, also known as the Basilica of St. Louis, King of France, is the seat of the Roman Catholic Archdiocese of New Orleans; it has the distinction of being the oldest continuously operating cathedral in the United States. The first church on the site was built in 1718; the third, built in 1789, was raised to cathedral rank in 1793. The cathedral was expanded and largely rebuilt in 1850, with little of the 1789 structure remaining.
Saint Louis Cathedral is in the French Quarter of New Orleans, Louisiana, USA, on the Place John Paul II (French: Place Jean-Paul II), a promenaded section of Chartres Street (rue de Chartres) that stretches one block between St. Peter Street (rue Saint-Pierre) on the upriver boundary and St. Ann Street (rue Sainte-Anne) on the downriver boundary. It is located next to Jackson Square and facing the Mississippi River in the heart of New Orleans, situated between the historic buildings of the Cabildo and the Presbytère. It is one of the few Roman Catholic churches in the United States that fronts a major public square.