It is the seat of the Diocese of Peoria, where the Catholic televangelist and sainthood candidate Archbishop Fulton J. Sheen was born and raised, and ordained a priest.

The first Mass in the vicinity of Peoria was celebrated at Fort Crevecoeur, across the Illinois River from the present city.

The exterior is composed of Anamosa Limestone and the twin spires on the main façade rise to a height of 230 feet (70 m).

As a child, Sheen served as an altar boy in St. Mary's Cathedral and he was ordained a priest here in 1919 for the Diocese of Peoria, which has sponsored his cause for canonization.

[9] Media related to Cathedral of Saint Mary of the Immaculate Conception (Peoria, Illinois) at Wikimedia Commons