***U.S. Congregational Membership Reports are provided by the Association of Religion Data Archives (ARDA). These online reports are based on data from the Glenmary Research Center and later also the Association of Statisticians of American Religious Bodies. The data is available in the archive.
Books reporting the data are also available:
Map and reports with the data from the Religious Congregations and Membership study are available in Social Explorer (in cooperation with ARDA). These maps provide counts of adherents and congregations at the county level for most denominations in the United States. Available for the years 1980, 1990, 2000, and 2009-2010.
InfoGroup American Church Lists is a database compiled by the InfoGroup direct marketing company. Data on membership and congregations in 2009 has been organized by ARDA and is available in Social Explorer.
National Congregations Study is an ongoing national survey effort to gather information about the basic characteristics of America's congregations. The first wave of the NCS took place in 1998; Wave II was fielded in 2006-07. Online analysis options are available through this website.
Summaries of Congregational Research - this webpage from the Hartford Insitute for Religion Research offers summaries of major research projects which have the congregation as a focus of study.
The U.S. Congregational Life Survey was conducted in April 2000 by surveying a nationally representative sample of about 300,000 worshipers in over 2,000 congregations covering the attitudes, opinions, and perceptions of worshipers. The survey was sponsored by the Presbyterian Church, the Lily Endowment, and others. Sample excerpts from the study are available online. Data from this survey are available in ARDA.
This series was called the Yearbook of American Churches from 1952-1972 and the Yearbook of American and Canadian Churches from 1973-present. Includes membership statistics and selected statistics of church finances. Issued by the National Council of the Churches of Christ in the USA. Spring, 2019 this is on hiatus as a print publication. It is being re-envisioned as an online publication called Yearbook of Churches and is under the leadership of the Association of Statisticians of American Religious Bodies. See next two entries.
Developing online version of the Yearbook of American and Canadian Churches.This resource has been the definitive handbook of information about denominations since 1916. The goal of the online site is to offer: statistics of church membership and finance; descriptions of denominations; listings of denominations by families; names, postal and e-mail addresses of religious group leaders and headquarters. They are working with the Lake Institute, Indiana University,and the Lilly Foundation. The Browse tab at the top of the page offers access to the information that is presently available online.
Association of Statisticians of American Religious Bodies
Working with the developing online Yearbook of Churches. They gather statistics on American religious bodies. Their products/projects include adherents, cultural group adherents, and U.S. Religion Census.
The North American Muslim Resource GuideARDA National Profiles are available for most countries of the world. Be sure to consult the Data Sources page for a listing of valuable sources for further information.