Catholic Church had approximately 628,405 members, the Assyrian Church of the East 323,300, while the Ancient Church of the East had 100,000. Assyrian Church of the East – 0.5 million Ancient Church of the East – 0.1 million See also Christian state List of Christian denominations List of current Christian leaders List of largest church buildings List of schisms in Christianity List of the largest Protestant denominations Major religious groups References External links Yearbook of American and Canadian Churches National Council of Churches USA Pew Research Center – News Release 2002 (archived 1 November 2006) Pew Research Center – 2015 America's Changing Religious Landscape Association of Religion Data Archives Christian denominations