Quick Facts

• http://www.thearda.com/  
  American Religion Data Archive
  The ARDA collection includes quantitative data on churches and church membership, religious professionals, and religious groups (individuals, congregations and denominations), with strongest holdings on religion in the United States. It is possible to search across different data sets, and even to create maps for county, city or state data, etc. The site is best viewed with Internet Explorer.
•   http://www.adherents.com/.
  A good source for statistical and geographic information on the religions and religious movements of the world.  Data is taken from both primary research sources such as government census reports, statistical sampling surveys and organizational reporting, as well as citations from secondary literature which mention adherent statistics.  
• The Pluralism Project at Harvard University: Statistics Section
  The Pluralism Project's statistics section is a valuable resource for information on non-Christian, non-Jewish religions in the U.S..  Instead of listing a single number, this site gives the numbers produced by several different statistical agencies. 
• Wadsworth Religion Course Guide: Religion Maps
  Provides historical and modern maps pertaining to religion.  Some of these include:  Modern Distribution of World Religions, Centers of Early Buddhism, Dispersion of Islam through 1800 C.E.
• Interfaith Calendar. 
  Gives concise definitions of religious feast days and dates for them day by day, month by month and year by year, for several years in advance.  The site's creator is Delton Krueger of Hamline University in Minnesota.   
• Pew Forum On Religion and Public Life.
  Pew Research Center. The Pew Forum delivers timely, impartial information to national opinion leaders, including government officials and journalists. As a nonpartisan, non-advocacy organization, the Forum does not take positions on policy debates. As a clearinghouse, it gathers and disseminates objective information through polls and reports. As a town hall, it provides a neutral venue through its various issue roundtables and briefings for discussions of important issues where religion and domestic and international politics intersect. Its areas of focus include religion and politics, religion and law, religion and domestic policy and religion and world affairs.  
• World Christian Encyclopedia : A Comparative Survey of Churches and Religions in the Modern World. David B. Barrett et al. 
  Reference BR 157 .W57 2001
  The first volume of this two-volume work contains "The World by Countries: Religionists, Churches, Ministries."  The second volume covers "The world by segments: religions, peoples, languages, cities, topics."  Maps, graphics, indexes and a bibliography are included.  
• Illustrated Book of World Rankings. Thomas Kurian, Ed. 
  Ellis Reference HA 155 .K87 2001
  This book makes statistical comparisons across countries in many areas of social life, including religion. 
• Chronological and Background Charts of Church History. Walton, Robert C.   
  Ellis Stacks BR146 .W33 1986
  This is a good place to find charts showing the history of the different Christian churches, and representations of various schisms and splits throughout history.