The Census Bureau conducted censuses of religious bodies at 10-year intervals from 1906 through 1936. The results were published with statistics on topics such as the number of members in congregations, number of church edifices, seating capacity, value and debt on church property, and so forth. The census publications varied with the first two having volumes of reports and the 1926 and 1936 censuses releasing a Summary report and a second volume made up of individual reports on the denominations listed in the census. See our detailed listing of reports from past censuses (1790 on).

There also was a survey of religious affiliation done as part of the Current Population Survey in 1957 with the results published in a report entitled, "Religion Report by the Civilian Population of the United States, March 1957." The Census of Religious Bodies began as a few questions on the Social Statistics form of the 1850 census. When the Bureau became permanent in 1902, it became possible to separate some data collection from the decennial census. The Census of Religious Bodies was a stand-alone census taken every  10 years between 1906 and 1936. Data were collected in 1946 but the funding for tabulation was not forthcoming. The entire census was eliminated in the mid 1950's. Copies of the report are in the U.S. National Archives and Records Administration (http://www.nara.gov).

The U.S. Census Bureau does not collect data on religious affiliation in its demographic surveys or decennial census. Public Law 94-521 prohibits us from asking a question on religious affiliation on a mandatory basis; in some person or household surveys, however, the U.S. Census Bureau may collect information about religious practices, on a voluntary basis. Therefore, the U.S. Census Bureau is not the source for information on religion, nor is the Census Bureau the source for information on religious affiliation. Some statistics on religion can be found in the Statistical Abstract of the United States, Section 1, Population.