U.S./Chicago Metro.

Sources for Demographic Data:

www.peoplegroups.org
also see companion page www.peoplegroups.info

U. S. Census Bureau
also see companion page www.census.gov/main/www/cen2000.html

   Chicago's Ethnic Mosaic

Chicago Police Department

Zip Skinny (probably reliable)

Hello Chicago (probably reliable)

City-Data (commercial site)

Also see: county courthouse, city hall, chamber of commerce, hospitals & other emergency services, local newspapers & other media

International

Research Sources:

Center for the Study of Global Christianity

Christian Research

Ministry Research

International Bulletin of Missionary Research

World Christian Database 

Each of the above sources has multiple links that may also prove to be helpful