- Adherents.com
- Data on religious group membership.
- American Religion Data Archive
- Preserves and provides access to data on American religion.
- General Social Surveys
- Personal opinion surveys of U.S. households conducted regularly since 1972 by the National Opinion Research Center.
- Inter-University Consortium for Political and Social Research
- Vast archive of social science data for researchers.
- Pew Forum on Religion and Public Life
- A project of the Pew Research Center, provides survey data, news and publications.