Faith-Based Organization Adherents
This indicator reports the total count of faith-based organization adherents in 2020 as a percentage of total population. A religious diversity index is also reported measuring how diverse the report area’s religious composition is, relative to national proportions. The higher the index, the more religious diversity in the report area.
Source
Original data compiled by 2020 U.S. Religion Census (Religious Congregations & Membership Study, RCMS). Data accessed via Social Explorer’s Religion (RCMS) dataset. Additional data analysis by CARES.
Source Description
The 2020 Religion (RCMS) database, compiled by the Association of Statisticians of American Religious Bodies (ASARB) in collaboration with the Church of the Nazarene and funded by foundations such as Lilly and Templeton, covers 372 religious bodies across the U.S. and includes data on 356,642 congregations with 161 million adherents—representing about 48.6 % of the 2020 U.S. population.
Data collection was conducted from June 2019 through October 2020, using a combination of denominational directories, yearbooks, targeted surveys to contact persons, and online research—supplemented with telephone, mail, web, and utility verification. Standardized quality checks and adjustments were finalized in June 2023.
ARDA categorizes and packages the cleaned dataset at county, state, metro, and national levels, adding summary variables such as religious tradition (RELTRAD) groups. In early 2024, ARDA introduced 21 new tradition-based variables.
The final data are publicly accessible via ARDA’s platform and are also compatible with Social Explorer for mapping, visualization, and analysis.
For full details on methodology and variable definitions, please visit ARDA’s U.S. Religion Census Maps and data files for 2020 webpage or download data from Social Explorer RCMS report.
Methodology
This indicator uses data from the 2020 U.S. Religion Census, conducted by the Association of Religion Data Archives (ARDA), which compiles self-reported statistics from religious bodies across the United States. The data reflect religious adherence at the county level based on counts of individuals affiliated with participating congregations.
It reports total population in 2020 (sourced from the U.S. Census Bureau), total number of individuals affiliated with any religious group, as reported by participating denominations (any religion) in the U.S. Religion Census, and the total percentage of population affiliated with any religion (calculated by CARES using total population as the denominator.)
It also reports the religious diversity index within a geographic area, based on a normalized version of the reciprocal of a Herfindahl-type index. This index accounts for the local distribution of religious adherents across major faith groups and adjusts for national religious composition. Higher values indicate a more religiously diverse population.
For more information, please go to ARDA’s U.S. Religion Census webpage.