As of 2010
The Catholic Church is the Biggest Christian Church in the US. With about 68,000,000 members.
The next is The Southern Baptist Convention with about 16,000,000 members.
The third is the United Methodist Church with about 7,000,000.
Approximately 3800 Christian churches are in the US. This answer probably left off 2 zeros at the end. Most estimates of Christian churches in the US range from 300,000 to 400,000.
The body of Christ
The religion of Jehovah's Witnesses is extremely small in size numbering only about 7 million, they are therefore not in the top ten in terms of size*. They are however one of the fastests growing CHRISTIAN groups in the world.According to the 2009 National Council of Churches report, of the 25 largest religions* in the United States, Jehovah's Witnesses are 1 of only 4 that have shown an increase.*They are the 12th largest CHRISTIAN denominiation in the US
43.9% have websites and there are 300k Christian churches - If these numbers are accurate, that would make 131,700 churches.
christian
Brazil has the second largest Christian population of any country, second to the US. Greece has the second largest Christian percentage of any country, second to the Vatican.
ny fl
Texas
The Catholic denomination is the largest Christian group in the world followed by protestants in England and the US.
I do not believe there is a list that has the top 500 churches in the US, but here is a list of the top 100 on the link below. The top ten on this list are (2009 reported weekend attendance):Lakewood Church, Houston TX (43,500)LifeChurch.tv, Edmond, OK (26,766)Willow Creek Community Church, South Barrington, IL (23,400)North Point Community Church, Alpharetta, GA (23,377)Second Baptist Church, Houston, TX (22,723)Saddleback Church, Lake Forest, CA (22,418)Fellowship Church, Grapevine, TX (18,355)Southern Christian Church, Louisville, KY (17,261)Woodlands Church, Woodlands, TX (17,142)Calvary Chapel Fort Lauderdale, Fort Lauderdale, FL (15,921)
I don't know the top 10 but I can tell you that C.R. England is the largest.
The Basilica of the Immaculate Conception in Washington, D.C. is the largest Catholic Church in the United States - of any name, and one of the ten largest Catholic Churches in the world, certainly the largest under the name of the Immaculate Conception.