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Cook County, Illinois

Religious Traditions, 2010

432,975 148,895 202,114 53,276 1,947,223 312,636 2,097,556
Evangelical Protestant Black Protestant Mainline Protestant Orthodox Catholic Other Unclaimed

Congregational adherents include all full members, their children, and others who regularly attend services. The 2010 reports contain incomplete counts of congregations and adherents belonging to the eight largest historically African-American denominations. These denominations are not included in the 2000 reports and are largely missing from the 1990 and 1980 reports.
[More information on the data sources]


Religious Bodies Tradition Family Congregations Adherents % Change
Southern Baptist Convention Evangelical Protestant Baptist +109 +28,828 +136.7%
Assemblies of God Evangelical Protestant Pentecostal +16 +24,755 +313.7%
Church of Jesus Christ of Latter-day Saints, The Other Latter-day Saints +10 +10,044 +155.4%
Seventh-day Adventist Church Evangelical Protestant Adventist +28 +8,881 +90.3%
Evangelical Free Church of America, The Evangelical Protestant Methodist/Pietist +9 +2,909 +88.4%
Church of God (Cleveland, Tennessee) Evangelical Protestant Pentecostal +0 +2,136 +59.1%
Evangelical Covenant Church, The Evangelical Protestant Methodist/Pietist +15 +1,471 +21.2%
Ukrainian Orthodox Church of the USA Orthodox Eastern Liturgical (Orthodox) +2 +1,400 +411.8%
Christian and Missionary Alliance, The Evangelical Protestant Holiness +16 +1,222 +99.9%
Armenian Apostolic Church of America (Catholicosate of Cilicia) Orthodox Eastern Liturgical (Orthodox) +0 +1,063 +243.2%
Churches of Christ Evangelical Protestant Restoration Movement +0 +996 +17.1%
Foursquare Gospel, International Church of the Evangelical Protestant Pentecostal +1 +911 +130.0%
Orthodox Presbyterian Church, The Evangelical Protestant Presbyterian-Reformed +4 +360 +800.0%
National Association of Congregational Christian Churches Mainline Protestant Presbyterian-Reformed +2 +200 +29.6%
Missionary Church, The Evangelical Protestant Holiness +5 +183 +67.5%
Church of the Nazarene Evangelical Protestant Holiness +10 +105 +2.1%
Cumberland Presbyterian Church Evangelical Protestant Presbyterian-Reformed +1 +53 +757.1%
Fellowship of Evangelical Churches Evangelical Protestant European Free-Church +0 -4 -5.3%
International Pentecostal Holiness Church Evangelical Protestant Pentecostal -1 -42 -64.6%
North American Baptist Conference Evangelical Protestant Baptist -1 -105 -11.9%
Church of the Brethren Evangelical Protestant European Free-Church +0 -144 -45.6%
Evangelical Congregational Church, The Evangelical Protestant Methodist/Pietist -2 -152 -100.0%
Free Methodist Church of North America Evangelical Protestant Holiness -1 -164 -19.4%
Protestant Reformed Churches in America Evangelical Protestant Presbyterian-Reformed +1 -173 -39.8%
Open Bible Standard Churches, Inc. Evangelical Protestant Pentecostal -1 -404 -75.5%
Christian Churches and Churches of Christ Evangelical Protestant Restoration Movement -6 -454 -12.4%
Metropolitan Community Churches, Universal Fellowship of Mainline Protestant Other Groups +0 -635 -79.4%
Syriac Orthodox Church of Antioch Orthodox Eastern Liturgical (Orthodox) -1 -685 -81.1%
Wisconsin Evangelical Lutheran Synod Evangelical Protestant Lutheran +2 -768 -32.9%
Salvation Army Evangelical Protestant Holiness +1 -820 -18.7%
Converge Worldwide/Baptist General Conference Evangelical Protestant Baptist +19 -904 -11.2%
Unitarian Universalist Association of Congregations Other Liberal -4 -1,893 -41.3%
Romanian Orthodox Archdiocese in Americas Orthodox Eastern Liturgical (Orthodox) +1 -2,217 -75.0%
Christian Church (Disciples of Christ) Mainline Protestant Restoration Movement -6 -2,651 -48.3%
American Baptist Churches in the USA Mainline Protestant Baptist -6 -3,352 -14.7%
Christian Reformed Church in North America Evangelical Protestant Presbyterian-Reformed -6 -3,816 -29.8%
Church of God (Anderson, Indiana) Evangelical Protestant Holiness +1 -4,626 -61.7%
Reformed Church in America Mainline Protestant Presbyterian-Reformed -10 -6,045 -52.1%
Christian Methodist Episcopal Church Black Protestant Methodist/Pietist +10 -7,799 -44.2%
Episcopal Church Mainline Protestant Episcopalianism/Anglicanism -20 -12,576 -40.0%
African Methodist Episcopal Zion Church Black Protestant Methodist/Pietist +3 -13,132 -81.6%
United Church of Christ Mainline Protestant Presbyterian-Reformed -18 -17,348 -30.3%
Presbyterian Church (U.S.A.) Mainline Protestant Presbyterian-Reformed -22 -21,200 -41.0%
United Methodist Church, The Mainline Protestant Methodist/Pietist -33 -37,464 -52.7%
Evangelical Lutheran Church in America Mainline Protestant Lutheran -42 -53,130 -51.6%
Lutheran Church--Missouri Synod Evangelical Protestant Lutheran -25 -55,385 -54.6%
Catholic Church Catholic Catholicism -60 -356,520 -15.5%
Brethren In Christ Church Evangelical Protestant European Free-Church --- --- ---
Christian Brethren Evangelical Protestant Ind. Fundamentalist -20 --- ---
Church of God (Seventh Day) Evangelical Protestant Adventist +3 --- ---
Conservative Baptist Association of America Evangelical Protestant Baptist -7 --- ---
Swedenborgian Church Other Spiritualist +0 --- ---
Totals: -23 -519,091 -18%

The population of Cook County, Illinois was 5,194,675 in 2010; in 2000 it was 5,376,741. The total population changed -3.4%. The adherent totals of the religious groups listed above (3,097,119) included 59.6% of the total population in 2010.

The population of Cook County, Illinois was 5,253,655 in 1980. The adherent totals of the religious groups listed above (2,967,455) included 56.5% of the total population in 1980.

* In an effort to better match the ASARB standards for adherents, a few religious bodies changed the way their adherents were reported in 2010, including the Catholic Church, Amish groups, Friends groups, Jewish groups, the Church of Jesus Christ of Latter-day Saints, Non-denominational Christian Churches, and the United Methodist Church. This change does not affect any of the data in the newly released 2010 U.S. Religion Census: Religious Congregations & Membership Study. In fact, the data for these groups are now more comparable to that of other bodies than it was in previous decadal reports.

However, the change in methodology can distort assessments on growth or decline between 2000 and 2010 for each of these groups. County-level 2000 data using the new methodology are not readily available. ASARB staff has adjusted some 2000 county-level adherent statistics to allow for a more accurate picture on growth or decline. The revised maps and charts are now available on-line at for those who are interested in these trends.


2010 data were collected by the Association of Statisticians of American Religious Bodies (ASARB) and include statistics for 236 religious groups, providing information on the number of their congregations and adherents within each state and county in the United States. Clifford Grammich, Kirk Hadaway, Richard Houseal, Dale E. Jones, Alexei Krindatch, Richie Stanley and Richard H. Taylor supervised the collection. These data originally appeared in 2010 U.S. Religion Census: Religious Congregations & Membership Study, published by the Association of Statisticians of American Religious Bodies (ASARB). [More information on the data collection]

The adherence rate provides the number of adherents of a particular group per 1,000 population. For example, in 2010 the Episcopal Church had an adherence rate of 7.6 in Autauga County, Alabama. This means that about 8 out of every 1,000 people in Autauga County were Episcopalian.

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