Below is a list of the 25 largest churches in the U.S. and Canada. Note that The Church of Jesus Christ of Latter-day Saints is listed as the 4th largest denomination.

1. The Catholic Church 68,202,492, [ranked 1 in 2011] , down 0.44%.
2. Southern Baptist Convention 16,136,044, [ranked 2 in 2011] , down 0.15%.
3. The United Methodist Church 7,679,850, [ranked 3 in 2011] , down 1.22%.
4. The Church of Jesus Christ of Latter-day Saints 6,157,238, [ranked 4 in 2011], up 1.62%.
5. The Church of God in Christ 5,499,875, [ranked 5 in 2011] , no update reported.
6. National Baptist Convention , U.S.A. , Inc. 5,197,512, [ranked 6 in 2011] , up 3.95%.
7. Evangelical Lutheran Church in America 4,274,855, [ranked 7 in 2011] , down 5.90%.
8. National Baptist Convention of America , Inc. 3,500,000, [ranked 8 in 2011] , no update reported.
9. Assemblies of God 3,030,944, [ranked 9 in 2011] , up 3.99%.
10. Presbyterian Church (U.S.A.) 2,675,873, [ranked 10 in 2011] , down 3.42%.
11. African Methodist Episcopal Church 2,500,000, [ranked 11 in 2011] , no update reported.
12. National Missionary Baptist Convention of America 2,500,000, [ranked 11 in 2011] , no update reported.
13. The Lutheran Church — Missouri Synod (LCMS) 2,278,586, [ranked 13 in 2011] , down 1.45%.
14. The Episcopal Church 1,951,907, [ranked 14 in 2011] , down 2.71%.
15. Pentecostal Assemblies of the World, Inc. 1,800,000, ranked 15 [ranked 17 in 2011] , up 20%.
16. Churches of Christ 1,639,495, [ranked 15 in 2011] , no update reported.
17. Greek Orthodox Archdiocese of America 1,500,000 , [ranked 16 in 2011] , no update reported.
18. The African Methodist Episcopal Zion Church 1,400,000, [ranked 18 in 2011] , no update reported.
19. American Baptist Churches in the U.S.A. 1,308,054, [ranked 19 in 2011] , down 0.19%.
20. Jehovah’s Witnesses 1,184,249, [ranked 20 in 2011] , up 1.85%.
21. Church of God ( Cleveland , Tennessee ) 1,074,047, [ranked 22 in 2011] , down 0.21%.
22. Christian Churches and Churches of Christ 1,071,616, [ranked 23 in 2011] , no update reported.
23. Seventh-day Adventist Church 1,060,386, [ranked 24 in 2011] , up 1.61%.
24. United Church of Christ 1,058,423, [ranked 21 in 2011], down 2.02%.
25. Progressive National Baptist Convention, Inc. 1,010,000, [ranked 25 in 2011 ], no update reported.

The list is from Fast Facts about American Religion by the Hartford Institute for Religion Research.

They report that the total membership in the top 25 churches is 145,691,446, down 1.15% from the previous year.

The growing denominations in 2011 were The Church of Jesus Christ of Latter-day Saints (“Mormons”), the Assembles of God, and several other Pentecostal groups; each reporting a 2% growth.

Mainline Protestant denominations continued to decline. The United Methodist Church, the Evangelical Lutheran Church in America, the Presbyterian Church USA, and the United Church of Christ, all reported decreases in membership in 2011. For several years now, the Southern Baptist Convention, a conservative evangelical denomination, also showed a decrease. The Roman Catholic Church also reported a decrease of less than 1%.