William Morgan Cassidy is an American physician and politician serving as the senior United States senator from Louisiana, a seat he has held since 2015. A member of the Republican Party, he served in the Louisiana State Senate from 2006 to 2009 and in the U.S. House of Representatives from 2009 to 2015.

Louisiana's 6th congressional district is a congressional district in the U.S. state of Louisiana. Located in south-central Louisiana, the district contains most of the state capital of Baton Rouge, the bulk of Baton Rouge's suburbs, and continues south to Thibodaux. It also includes the western shores of Lake Pontchartrain.