From CBSNews.com:

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. Visit this link for the churches.