Here is a list of the 15 largest religious denominations in the United States, according to the 2000 Religious Congregations & Membership study by the Glenmary Research Center:
Roman Catholic, 62,035,042 adherents
2. Southern Baptist Convention, 19,881,467
3. United Methodist Church, 10,350,629
4. Jewish (estimate), 6,141,325
5. Evangelical Lutheran Church in America, 5,113,418
6. The Church of Jesus Christ of Latter-day Saints, 4,224,026
7. Presbyterian Church (U.S.A.), 3,141,566
8. Assemblies of God, 2,561,998
9. Lutheran Church-Missouri Synod, 2,521,062
10. Episcopal Church, 2,314,756
11. American Baptist Churches in the USA, 1,767,462
12. United Church of Christ, 1,698,918
13. Churches of Christ, 1,645,584
14. Muslim (estimate), 1,559,294
15. Christian Churches and Churches of Christ, 1,439,253