Multiple denominations (each self-reported; see README for exceptions) · Compiled by this site from multiple public sources
A third "mixed data" entry, comparing ACROSS ten denominations rather than tracking one body over time: Catholic Church, United Methodist Church, The Church of Jesus Christ of Latter-day Saints, Evangelical Lutheran Church in America, Lutheran Church–Missouri Synod, Orthodox Christian churches (combined estimate), Episcopal Church, Presbyterian Church (USA), Church of God in Christ, and Presbyterian Church in America. For each, an ordinary-least-squares line is fit through that body's own reported membership figures and extended to 2035 — a blunt straight-line extrapolation, not a demographic forecast, modeled on Ryan Burge's GSS-based American-religion projections (gist.github.com/ryanburge/e785275206cd12584b73eb4ec9b3ad52). Several entries carry real data-quality caveats — Catholic figures vary 5-15M by methodology, LDS figures are worldwide rather than U.S.-only, and Orthodox/COGIC figures are sparse and, for COGIC, diverge roughly 5-6x from independent U.S. Religion Census counts. See docs/datasets/ten-largest-us-churches-2035/README.md for every figure's exact citation and confidence rating.