We're living in the era of the megachurch. The United States has more than 1,300 megachurches, according to the Hartford Institute for Religious Research, which defines them as very active Protestant congregations with an average of 2,000 or more weekend attendees and a multitude of outreach programs and ministries.

That research also finds roughly 50 churches have a weekly attendance between 10,000 to 47,000 people. Here are the biggest megachurches in the country, based on the number of weekly visitors. 

The First Baptist Church of Hammond, in Indiana, has about 17,700 weekly visitors. 

Sagemont Church of Houston also has about 17,700 weekly visitors. 

The Living Word Christian Center, a non-denominational church in Chicago, has about 18,000 weekly visitors. 

The Temple of Praise in Washington, D.C., also has about 18,000 weekly visitors. 

The Woodlands Church in Texas has about 18,400 weekly visitors. 

Calvary Chapel Fort Lauderdale, in Florida, has about 18,500 weekly visitors. The church has 30,000 members. 

Christ Fellowship in Palm Beach Gardens, Florida, has about 19,000 weekly visitors.  

Elevation Church, which has locations in North Carolina, South Carolina, Florida and Virginia, has about 19,000 weekly visitors. 

Greater Allen A. M. E. Cathedral, in the Queens borough of New York City, has about 20,000 weekly visitors. 

Greater Cornerstone Baptist Church in Dallas also has about 20,000 weekly visitors. 

New Light Christian Center Church in Houston has about 20,000 weekly visitors. 

West Angeles Cathedral in Los Angeles has about 20,000 weekly visitors. 

Dream City Church, an Assemblies of God church in Phoenix, has about 21,000 weekly visitors. 

Central Christian Church in Nevada has about 21,100 weekly visitors. 

Southeast Christian Church in Kentucky has about 21,800 weekly visitors. 

Northland, A Church Distributed in Longwood, Florida, has about 22,000 weekly visitors. 

Saddleback Church in Lake Forest, California, has about 22,100 weekly visitors. 

Pastor Rick Warren, who founded the church, developed a national following with his best-selling books, including "A Purpose Driven Life."

Crossroads Church - Cincinnati, an interdenominational church, has about 22,700 weekly visitors. 

Second Baptist Church Houston has about 23,700 weekly visitors. 

Faith Church, which has four campuses in Missouri and Florida, has about 25,000 weekly visitors. 

Willow Creek Community Church, in Illinois, has about 25,800 weekly visitors. 

Gateway Church, in Texas, has about 27,000 weekly visitors. The church has about 36,000 members. 

Christ's Church of the Valley, in a suburb of Phoenix, Arizona, has about 27,000 weekly visitors. 

First Baptist Church of Jacksonville, Florida, has about 28,000 weekly visitors.

The Christian Cultural Center, in Brooklyn, New York, has about 30,000 weekly visitors.

NewSpring Church, in South Carolina, has about 31,800 weekly visitors. 

North Point Community Church, in a suburb of Atlanta, Georgia, has about 36,000 weekly visitors. 

Lakewood Church in Houston has about 43,500 weekly visitors. 

Joel Osteen, whose sermons are often televised, is the pastor there. 

Church of the Highlands in Birmingham, Alabama, has about 43,600 weekly visitors.