Martin John Spalding was an American prelate of the Roman Catholic Church. He served as bishop of the Diocese of Louisville in Kentucky (1850–1864) and as archbishop of the Archdiocese of Baltimore (1864–1872). He advocated aid for freed slaves following the American Civil War. Spalding attended the First Vatican Council, where he first opposed, and then supported, a dogmatic proclamation of papal infallibility.

The Archdiocese of Louisville is a Latin Church ecclesiastical territory, or archdiocese, of the Catholic Church in central Kentucky in the United States. The cathedral church of the archdiocese is the Cathedral of the Assumption in Louisville, Kentucky. The archdiocese is the seat of the metropolitan see of the Province of Louisville, which encompasses the states of Kentucky and Tennessee. The archdiocese is the second-oldest diocese west of the Appalachian Mountains, after the Archdiocese of New Orleans. As of 2023, the archbishop of Louisville is Shelton Fabre.