The Basilica of Saint Louis, King of France, formerly the Cathedral of Saint Louis, and colloquially the Old Cathedral, was the first cathedral

Cathedral

A cathedral is a Christian church that contains the seat of a bishop...

 west of the Mississippi River

Mississippi River

The Mississippi River is the largest river system in North America. Flowing entirely in the United States, this river rises in western Minnesota and meanders slowly southwards for to the Mississippi River Delta at the Gulf of Mexico. With its many tributaries, the Mississippi's watershed drains...

 and until 1845 the only parish church

Parish church

A parish church , in Christianity, is the church which acts as the religious centre of a parish, the basic administrative unit of episcopal churches....

 in the city of St. Louis, Missouri

St. Louis, Missouri

St. Louis is an independent city on the eastern border of Missouri, United States. With a population of 319,294, it was the 58th-largest U.S. city at the 2010 U.S. Census. The Greater St...

. It is one of two Catholic

Roman Catholic Church

The Catholic Church, also known as the Roman Catholic Church, is the world's largest Christian church, with over a billion members. Led by the Pope, it defines its mission as spreading the gospel of Jesus Christ, administering the sacraments and exercising charity...

 basilica

Basilica

The Latin word basilica , was originally used to describe a Roman public building, usually located in the forum of a Roman town. Public basilicas began to appear in Hellenistic cities in the 2nd century BC.The term was also applied to buildings used for religious purposes...

s in St. Louis, and it is named for King Louis IX of France

Louis IX of France

Louis IX , commonly Saint Louis, was King of France from 1226 until his death. He was also styled Louis II, Count of Artois from 1226 to 1237. Born at Poissy, near Paris, he was an eighth-generation descendant of Hugh Capet, and thus a member of the House of Capet, and the son of Louis VIII and...

, also the namesake for the city of St. Louis.

It is located near the historic riverfront of St. Louis, surrounded by but not a part of the Gateway Arch

Jefferson National Expansion Memorial

The Jefferson National Expansion Memorial is in St. Louis, Missouri, near the starting point of the Lewis and Clark Expedition. It was designated as a National Memorial by Executive Order 7523, on December 21, 1935, and is maintained by the National Park Service .The park was established to...

 grounds.