Boundary County, Idaho has 12 churches in the Churches List directory, 0 of them verified and 1 with a published website. The 2020 US Religion Census counted 25 congregations and 4,377 adherents across 21 religious bodies in the county. That is 363 adherents per 1,000 residents of its 12,057 people.
| Religious body | Congregations | Adherents | Per 1,000 pop. |
|---|---|---|---|
| Catholic Church | 1 | 915 | 75.9 |
| Southern Baptist Convention | 2 | 530 | 44.0 |
| Church of Jesus Christ of Latter-day Saints | 2 | 506 | 42.0 |
| Non-denominational Christian Churches | 3 | 500 | 41.5 |
| Church of Christ, Mennonite | 2 | 490 | 40.6 |
| Unaffiliated Conservative Mennonite | 1 | 250 | 20.7 |
| Seventh-day Adventist Church | 1 | 210 | 17.4 |
| Jehovah's Witnesses | 1 | 134 | 11.1 |
| Antiochian Orthodox Christian Archdiocese of North America, The | 1 | 125 | 10.4 |
| Assemblies of God | 1 | 121 | 10.0 |
| Evangelical Lutheran Church in America | 1 | 109 | 9.0 |
| Old German Baptist Brethren | 1 | 98 | 8.1 |
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 (12,057). Largest 12 bodies by adherents shown.
Directory traditions here: Non-Denominational (1) · Baptist Churches (1) · Methodist (1) · Lutheran (1) · Episcopal (1) · Catholic (1) · United Methodist (1) · Church of Christ (1) · Community (1) · Seventh Day Adventist (1)
Directory listings are mapped to Boundary 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.