Union County, Iowa has 39 churches in the Churches List directory, 0 of them verified and 9 with a published website. The 2020 US Religion Census counted 28 congregations and 4,249 adherents across 20 religious bodies in the county. That is 350 adherents per 1,000 residents of its 12,142 people.
| Religious body | Congregations | Adherents | Per 1,000 pop. |
|---|---|---|---|
| Catholic Church | 2 | 1,370 | 112.8 |
| United Methodist Church | 6 | 697 | 57.4 |
| Southern Baptist Convention | 1 | 363 | 29.9 |
| United Church of Christ | 2 | 328 | 27.0 |
| Lutheran Church--Missouri Synod | 1 | 288 | 23.7 |
| Non-denominational Christian Churches | 1 | 260 | 21.4 |
| Presbyterian Church (U.S.A.) | 2 | 180 | 14.8 |
| Jehovah's Witnesses | 1 | 176 | 14.5 |
| Amish Groups, undifferentiated | 2 | 172 | 14.2 |
| Tampico Amish-Mennonite | 1 | 145 | 11.9 |
| Evangelical Lutheran Church in America | 1 | 143 | 11.8 |
| Assemblies of God | 1 | 44 | 3.6 |
Source: 2020 US Religion Census (Association of Statisticians of American Religious Bodies). Per-1,000 rates divide reported adherents by the county's 2020 Census population (12,142). Largest 12 bodies by adherents shown.
Directory traditions here: Methodist (9) · Baptist Churches (4) · United Church of Christ (3) · Catholic (3) · Non-Denominational (2) · Lutheran (2) · United Methodist (2) · Church of Christ (2) · Assemblies of God (2) · Apostolic (1)
Directory listings are mapped to Union County through the US Census Bureau's 2020 ZCTA-to-county relationship file: each ZIP Code Tabulation Area is assigned to the county holding the largest share of its land area, so a small number of churches in ZIP codes that straddle county lines may be attributed to a neighboring county. Congregation and adherent counts come from the 2020 US Religion Census and are reported by the religious bodies themselves. Population is the county's April 2020 decennial-census base from the US Census Bureau's population-estimates program; per-1,000 adherence rates divide reported adherents by that figure. Corrections to any listing go through the corrections page.