The diocese was founded in 1835 as the Episcopal Diocese of Illinois. Philander Chase, the retired bishop of Ohio, was the first bishop. He was succeeded in 1852 by Henry John Whitehouse, a priest previously from New York. Edward McLaren, elected bishop in 1875, saw the Diocese of Illinois divided into three parts in 1877. The newly formed dioceses of Quincy and Springfield elected their own bishops, while McClaren's diocese was renamed the Episcopal Diocese of Chicago.
Present day
The Diocese of Chicago ranks among the 12 largest Episcopal dioceses in the United States, with 137 congregations, of which 36 are missions. However, in parallel with declining national memberships, the diocese has seen a decline in membership: 47,171 baptized members in 1994, but only 42,667 in 1996. As of 2011 the diocese website said it had 40,000 members. The diocese is far more ethnically diverse than the Episcopal Church at large. There are four Hispanic congregations, one of which is located in the near western suburbs of Chicago. In addition, four congregations outside Chicago provide Spanish language services, and two others share their facilities with congregations of the Philippine Independent Church. There is one Korean American congregation, and the diocese also serves eight African-American congregations. Minority outreach, like the kind found at the Cathedral Shelter of Chicago continues to this day. The 25th Presiding Bishop of the Episcopal Church, Frank Griswold, was bishop of Chicago when he was elected in 1997. The current bishop, Jeffrey Lee, assumed office in 2008. On February 14, 2019, Lee announced his intention to retire in August 2020.
Reunification
In 2008, a majority of laity and clergy in the neighboring Episcopal Diocese of Quincy left to form a diocese in the more conservative Anglican Church in North America. The remaining Episcopalians in Quincy reformed their diocese, electing John Buchanan, retired Bishop of West Missouri as their provisional bishop. In 2012 Quincy officials approached Lee and the leadership of the Chicago diocese about the possibility of reunification with Chicago. In November 2012 the Chicago diocese's convention agreed that reunification with the Quincy diocese should be pursued. On June 8, 2013, both diocesan conventions voted unanimously to reunify. The reunification was ratified by a majority of bishops and the standing committees of the Episcopal Church, and on September 1, 2013, the Diocese of Quincy merged into the Diocese of Chicago as the PeoriaDeanery.
