Largest Religious Groups in the United States

Adherents (growing collection of over 43,870 adherent statistics and religious geography citations: references to published membership/adherent statistics and congregation statistics for over 4,200 religions, churches, and denominations)

American Religion Data Archive

Gallup Polling Data About Religious Preference Over Last 10 years

List of Christian Denominations by Number of Members (Worldwide)

Most Ubiquitous Churches in the U.S., 1990

Religious Bodies which are the Largest Church in One or More U.S. States, 1990

Top 10 Largest Religious Bodies in the United States

Top 10 Religious Bodies with Most Churches in the U.S., 1990

Top 13 Largest Denominational Families in the U.S., 2001 (based on church attendance)

Top 13 Largest Denominational Families in the U.S., 2001 (self-identification)