Baton Rouge is the capital of the State of Louisiana, USA. State Capitol BuildingThe city of Baton Rouge was named over 300 years ago when on March 17, 1699, Pierre Le Moyne, Sieur d'Iberville, led an expedition along the Mississippi River. The city's earliest written records are found in the diaries of these explorers which tell the tale of a pole stained with blood of fish and animals that served as the dividing line between the Bayougoula and Houmas Indians. It is from this red stick that Iberville christened our city le Baton Rouge. The city's earliest written records are found in the diaries of these explorers which tell the tale of a pole stained with blood of fish and animals that served as the dividing line between the Bayougoula and Houmas Indians. It is from this red stick that Iberville christened our city le Baton Rouge.