This is a list of the largest Protestant churches in the United States with more than 1,000 members. Most of these are considered megachurches, while some fall outside this definition. The Hartford Institute's database lists more than 1,300 such Protestant churches in the United States. According to that data, approximately 50 churches on the list have attendance ranging from 10,000 to 47,000.
The Catholic Church is not measured similarly as it doesn't meet the characteristics of a megachurch. About 3,000 Catholic churches have 2,000+ attending each week, which is more than the 2,000 members for listing here. St Ann's in Coppell, Texas, would be near the top, with almost 30,000 registered parishioners.
Membership numbers give only a very rough indication of size. They vary from year to year. Also, some churches report typical Sunday attendance while others report the number who are listed in church records or make financial contributions, which may be higher. Some of the larger churches are multi-site churches. Many churches deliver their message through television or other media, sometimes reaching much higher numbers than those who physically attend the church.