Religion & the US Census
Historical Census Browser (UVA)
The US census included questions pertaining to religious affiliation from 1850-1950. Use the Census Browser to explore this historic data.
Religious Bodies (1906-1936)
The Census Bureau collected information on religious bodies from 1906-1936. See also: 1906 Special Report on African American Religious Bodies.
A Brief History of Religion and the U.S. Census: Overview from the Pew Forum on the history of religious questions appearing on the US Census. Questions about religion have not appeared on the census since the 1950s. In 1976, Congress made this official by amending the census law to prohibit any mandatory question pertaining to a person's "religious beliefs or to membership in a religious body."
Association of Religion Data Archives
The ARDA is an essential access point to quantitative data sets on religion. The site aggregates data from a wide variety of sources, covering all subjects, from congregational statistics to religious profiles for countries worldwide. Users can view reports, maps, and charts, or download raw data files for analysis with statistical software. While some international data sets are available, the greatest strength of the ARDA is its collections of data on religion in the United States.