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Washington County (Iowa)

Religious Traditions, 2010

4,150 4,170 3,956 189 9,239
Evangelical Protestant Mainline Protestant 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 Adherence Rate
American Baptist Churches in the USA Mainline Protestant Baptist 3 854 42.40
Assemblies of God Evangelical Protestant Pentecostal 1 118 5.86
Catholic Church Catholic Catholicism 5 4,472 222.03
Christian Church (Disciples of Christ) Mainline Protestant Baptist 3 681 33.81
Christian Churches and Churches of Christ Evangelical Protestant Baptist 1 36 1.79
Church of Jesus Christ of Latter-day Saints, The Other Latter-day Saints 1 39 1.94
Church of the Nazarene Evangelical Protestant Holiness 1 48 2.38
Churches of God, General Conference Evangelical Protestant Presbyterian-Reformed 0 0 0.00
Congregational Christian Churches, Additional (not part of any national CCC body) Mainline Protestant Presbyterian-Reformed 0 0 0.00
Converge Worldwide/Baptist General Conference Evangelical Protestant Baptist 1 177 8.79
Evangelical Lutheran Church in America Mainline Protestant Lutheran 1 407 20.21
Friends (Quakers) Mainline Protestant European Free-Church 1 24 1.19
Lutheran Church--Missouri Synod Evangelical Protestant Lutheran 1 70 3.48
Mennonite Church Evangelical Protestant European Free-Church 5 1,031 51.19
Mennonite Church, The General Conference Evangelical Protestant European Free-Church 1 103 5.11
Old Order Amish Evangelical Protestant European Free-Church 0 0 0.00
Presbyterian Church (U.S.A.) Mainline Protestant Presbyterian-Reformed 4 1,409 69.96
Reformed Presbyterian Church of North America Evangelical Protestant Presbyterian-Reformed 1 112 5.56
Seventh-day Adventist Church Evangelical Protestant Adventist 1 27 1.34
United Methodist Church, The Mainline Protestant Methodist/Pietist 9 3,406 169.11
Totals: 40 13,014  

The population of Washington County, Iowa was 20,141 in 1980. The adherent totals of the religious groups listed above (13,014) included 64.6% 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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