The Roman Catholic Archdiocese of Indianapolis () is a division of the Roman Catholic Church in the United States. When it was originally erected as the Diocese of Vincennes on May 6, 1834, it encompassed all of Indiana as well as the eastern third of Illinois. It was renamed the Diocese of Indianapolis on March 28, 1898. Bishop Francis Silas Chatard, who had been living in Indianapolis since 1878 when he was appointed Bishop of Vincennes, became the first Bishop of Indianapolis. It was elevated from a diocese to a metropolitan archdiocese on October 21, 1944.