Basilica of Saint Louis, King of France

The Basilica of Saint Louis, King of France, formerly the Cathedral of Saint Louis, and colloquially the Old Cathedral, is a Catholic church in St. Louis, Missouri. It was the first cathedral west of the Mississippi River and until 1844 the only parish church in St. Louis. It is one of two Catholic basilicas in St. Louis and both are named for King Louis IX of France.The current structure is located near the historic riverfront of St. Louis. It is surrounded by Gateway Arch National Park. However, the church is not part of the park. Because of the historical significance of the church, it was left intact while all neighboring buildings were demolished to make way for the Gateway Arch and related park. Rev. Nicholas Smith serves as Rector.

The basilica serves as a personal parish church rather than a territorial parish church. It ranks 177th of 196 churches in number of Catholics per church in the Archdiocese of St.