Episcopal Diocese of Quincy

The Diocese of Quincy was a diocese of the Episcopal Church in western Illinois from 1877 to 2013. The cathedral seat (home of the diocese) was originally in Quincy, Illinois but was moved to St. Paul's Cathedral in Peoria in 1963. In order to avoid confusion with the Roman Catholic Diocese of Peoria, the diocese retained the name of the location of its original "home" city, Quincy, where its cathedral seat was St. John's.

In November 2008, a majority of the diocesan synod (or diocesan convention) voted to leave the Episcopal Church and associate with Anglican Province of the Southern Cone, a member province of the worldwide Anglican Communion, as part of the conservative Anglican realignment movement. Those parishes and parishioners who did not vote to leave the Episcopal Church remained and continued as the Diocese of Quincy which, in 2013, merged into the Episcopal Diocese of Chicago.