According to a study by the Association of Statisticians of American Religious Bodies, the top ten religious denominations in the United States are (with number of members in millions):
Roman Catholic 53.4
Southern Baptist Convention 18.9
United Methodist 11.1
Black Baptist 8.7
Jewish 6.0
Evangelical Lutheran Church in America 5.2
Presbyterian 3.6
Church of Jesus Christ of Latter-Day Saints 3.5
Lutheran Church-Missouri Synod 2.6
Episcopal 2.4