Baton Rouge is the capital city of Louisiana. Much of the Pelican Brief involves the state of Louisiana. Darby is a law student at Tulane in New Orleans, and she speculates in the "Pelican Brief" that the murder of the two Supreme Court justices may have been related to the fact that they both opposed drilling for oil in an area in Louisiana, and would have ruled to that effect in a case that was to come before the court. The city is not central to the story, but is mentioned in passing throughout the book. For example, when Darby flees New Orleans, fearing for her life, Baton Rouge is her destination. She even pays a taxi driver 200 dollars to drive her there. So Baton Rouge is basically an important city in the state where much of the action in the Pelican Brief takes place.