| Denomination | Adherents in 2000 | Congregations in 2000 | Counties in 2000 | Adherent Change # | Congregation Change # | County Change # | Adherent Change % | Congregation Change % | County Change % |
| Totals from newly published book | Change from 1990 to 2000 | Change from 1990 to 2000 | |||||||
| Albanian Orthodox Diocese of America | 395 | 2 | 2 | NA | - | - | NA | 0.0% | 0.0% |
| Allegheny Wesleyan Methodist Connection | 1,864 | 115 | 61 | (662) | (5) | (1) | -26.2% | -4.2% | -1.6% |
| American Baptist Association, The | 280,973 | 1,867 | 594 | New to Study in 2000 | NA | NA | 0.0% | ||
| American Baptist Churches in the USA | 1,767,462 | 5,555 | 1,111 | (106,269) | (246) | (35) | -5.7% | -4.2% | -3.1% |
| American Carpatho-Russian Orthodox Greek Catholic Church | 20,000 | 75 | 52 | 5,390 | 6 | 4 | 36.9% | 8.7% | 8.3% |
| Amish; Other Groups | 6,671 | 90 | 56 | New to Study in 2000 | New to Study in 2000 | ||||
| Antiochian Orthodox Christian Archdiocese of North America, The | 82,374 | 210 | 160 | New to Study in 2000 | New to Study in 2000 | ||||
| Apostolic Catholic Assyrian Church of the East, North American Dioceses | 35,118 | 18 | 14 | 472 | 1 | (37) | 1.4% | 5.9% | -72.5% |
| Apostolic Christian Church of America, Inc. | 23,980 | 84 | 73 | 4,171 | 5 | 6 | 21.1% | 6.3% | 9.0% |
| Apostolic Christian Churches (Nazarean) | 4,393 | 50 | 38 | 877 | 2 | 1 | 24.9% | 4.2% | 2.7% |
| Armenian Apostolic Church / Catholicossate of Cilicia | 46,354 | 38 | 33 | (26,946) | 16 | 12 | -36.8% | 72.7% | 57.1% |
| Armenian Apostolic Church / Catholicossate of Etchmiadzin | 91,513 | 89 | 70 | New to Study in 2000 | New to Study in 2000 | ||||
| Assemblies of God | 2,561,998 | 11,880 | 2,616 | 400,388 | 731 | (10) | 18.5% | 6.6% | -0.4% |
| Associate Reformed Presbyterian Church | 40,397 | 242 | 115 | 2,409 | 55 | 21 | 6.3% | 29.4% | 22.3% |
| Association of Free Lutheran Congregations, The | 32,098 | 234 | 146 | 4,782 | 31 | 21 | 17.5% | 15.3% | 16.8% |
| Bahá'í | 146,756 | 1,198 | 2,407 | New to Study in 2000 | New to Study in 2000 | ||||
| Baptist General Conference | 238,920 | 866 | 346 | 71,046 | 80 | (51) | 42.3% | 10.2% | -12.8% |
| Baptist Missionary Association of America | 295,239 | 1,322 | 358 | 5,270 | (52) | (46) | 1.8% | -3.8% | -11.4% |
| Beachy Amish Mennonite Churches | 9,422 | 102 | 78 | 1,179 | 11 | 1 | 14.3% | 12.1% | 1.3% |
| Brethren Church, The (Ashland, Ohio) | 16,266 | 119 | 73 | (65) | (5) | (7) | -0.4% | -4.0% | -8.8% |
| Brethren In Christ Church | 25,512 | 216 | 88 | 5,743 | 28 | (13) | 29.1% | 14.9% | -12.9% |
| Bruderhof Communities, Inc. | 924 | 7 | 4 | New to Study in 2000 | New to Study in 2000 | ||||
| Buddhism | 1,656 | 359 | New to Study in 2000 | New to Study in 2000 | |||||
| Bulgarian Orthodox Diocese of the USA | 5,340 | 9 | 9 | New to Study in 2000 | New to Study in 2000 | ||||
| Calvary Chapel Fellowship Churches | 728 | 380 | New to Study in 2000 | New to Study in 2000 | |||||
| Catholic Church | 62,035,042 | 21,791 | 2,987 | 8,649,044 | (650) | 4 | 16.2% | -2.9% | 0.1% |
| Christian and Missionary Alliance, The | 331,106 | 1,878 | 709 | 59,241 | 81 | (77) | 21.8% | 4.5% | -9.8% |
| Christian Church (Disciples of Christ) | 1,017,784 | 3,339 | 1,290 | (19,973) | (696) | (156) | -1.9% | -17.2% | -10.8% |
| Christian Churches and Churches of Christ | 1,439,253 | 5,471 | 1,600 | 226,065 | 233 | (104) | 18.6% | 4.4% | -6.1% |
| Christian Reformed Church in North America | 248,938 | 740 | 236 | 22,775 | 24 | (26) | 10.1% | 3.4% | -9.9% |
| Christian Union | 7,319 | 114 | 59 | New to Study in 2000 | NA | NA | 0.0% | ||
| Church of God (Anderson, Indiana) | 238,609 | 2,286 | 990 | 5,733 | (50) | (131) | 2.5% | -2.1% | -11.7% |
| Church of God (Cleveland, Tennessee) | 974,198 | 5,612 | 1,595 | 279,124 | 616 | (137) | 40.2% | 12.3% | -7.9% |
| Church of God General Conference | 4,925 | 89 | 69 | (445) | 1 | (14) | -8.3% | 1.1% | -16.9% |
| Church of God in Christ, Mennonite | 15,337 | 100 | 82 | 2,802 | 25 | 16 | 22.4% | 33.3% | 24.2% |
| Church of God of Prophecy | 91,106 | 1,858 | 932 | (755) | (243) | (134) | -0.8% | -11.6% | -12.6% |
| Church of Jesus Christ of Latter-day Saints, The | 4,224,026 | 11,515 | 1,802 | 683,206 | 2,307 | (121) | 19.3% | 25.1% | -6.3% |
| Church of the Brethren | 171,281 | 1,074 | 432 | (15,307) | (47) | (31) | -8.2% | -4.2% | -6.7% |
| Church of the Nazarene | 907,331 | 5,209 | 1,858 | 19,208 | 42 | (104) | 2.2% | 0.8% | -5.3% |
| Churches of Christ | 1,645,584 | 13,027 | 2,429 | (35,429) | (70) | (61) | -2.1% | -0.5% | -2.4% |
| Churches of God, General Conference | 42,204 | 336 | 125 | 705 | (16) | (5) | 1.7% | -4.5% | -3.8% |
| Community of Christ | 98,874 | 892 | 615 | New to Study in 2000 | New to Study in 2000 | ||||
| Congregational Christian Churches, Additional (not part of any national CCC body) | 17,821 | 104 | 79 | (18,858) | (128) | (65) | -51.4% | -55.2% | -45.1% |
| Conservative Baptist Association of America | 224,306 | 1,191 | 418 | NA | 70 | (60) | NA | 6.2% | -12.6% |
| Conservative Congregational Christian Conference | 50,940 | 250 | 169 | 15,340 | 73 | 25 | 43.1% | 41.2% | 17.4% |
| Conservative Mennonite Conference | 14,865 | 104 | 59 | New to Study in 2000 | New to Study in 2000 | ||||
| Coptic Orthodox Church | 55 | 39 | New to Study in 2000 | New to Study in 2000 | |||||
| Cumberland Presbyterian Church | 77,686 | 706 | 269 | (13,354) | (31) | (47) | -14.7% | -4.2% | -14.9% |
| Duck River and Kindred Baptists Associations | 12,542 | 99 | 25 | (673) | (3) | 1 | -5.1% | -2.9% | 4.2% |
| Eastern Pennsylvania Mennonite Church | 4,384 | 49 | 34 | 503 | 2 | 5 | 13.0% | 4.3% | 17.2% |
| Enterprise Baptists Association | 5,289 | 65 | 26 | (712) | (5) | (1) | -11.9% | -7.1% | -3.7% |
| Episcopal Church | 2,314,756 | 7,314 | 2,118 | (130,530) | (19) | (40) | -5.3% | -0.3% | -1.9% |
| Evangelical Covenant Church, The | 153,116 | 671 | 312 | New to Study in 2000 | NA | NA | 0.0% | ||
| Evangelical Free Church of America, The | 285,699 | 1,365 | 720 | 104,007 | 319 | 124 | 57.2% | 30.5% | 20.8% |
| Evangelical Lutheran Church in America | 5,113,418 | 10,739 | 1,756 | (113,380) | (173) | 18 | -2.2% | -1.6% | 1.0% |
| Evangelical Mennonite Church | 6,625 | 34 | 23 | 1,503 | 8 | 2 | 29.3% | 30.8% | 9.5% |
| Evangelical Presbyterian Church | 80,207 | 179 | 121 | 34,743 | 41 | 16 | 76.4% | 29.7% | 15.2% |
| Fellowship of Evangelical Bible Churches | 1,811 | 17 | 15 | (278) | 1 | - | -13.3% | 6.3% | 0.0% |
| Free Methodist Church of North America | 96,237 | 950 | 480 | 13,471 | (88) | (121) | 16.3% | -8.5% | -20.1% |
| Friends (Quakers) | 113,086 | 1,302 | 573 | (17,398) | 6 | (147) | -13.3% | 0.5% | -20.4% |
| Fundamental Methodist Conference, Inc. | 1,009 | 13 | 7 | (28) | - | 1 | -2.7% | 0.0% | 16.7% |
| General Association of Regular Baptist Churches | 245,636 | 1,422 | 642 | New to Study in 2000 | New to Study in 2000 | ||||
| General Six Principle Baptists | 25 | 1 | 1 | (147) | (1) | (1) | -85.5% | -50.0% | -50.0% |
| Greek Orthodox Archdiocese of America | 427,659 | 518 | 336 | NA | 3 | 2 | NA | 0.6% | 0.6% |
| Greek Orthodox Archdiocese of Vasiloupulis | 30,148 | 38 | 30 | New to Study in 2000 | New to Study in 2000 | ||||
| Hindu | 629 | 206 | New to Study in 2000 | New to Study in 2000 | |||||
| Holy Orthodox Church in North America | 1,889 | 30 | 26 | New to Study in 2000 | New to Study in 2000 | ||||
| Hutterian Brethren | 12,300 | 123 | 60 | 1,263 | 12 | - | 11.4% | 10.8% | 0.0% |
| Independent Free Will Baptists Associations | 24,107 | 264 | 53 | New to Study in 2000 | New to Study in 2000 | ||||
| Independent, Charismatic Churches | 935,168 | 621 | 305 | 140,914 | (208) | 1 | 17.7% | -25.1% | 0.3% |
| Independent, Non-Charismatic Churches | 1,116,769 | 1,084 | 458 | (90,404) | (279) | (70) | -7.5% | -20.5% | -13.3% |
| International Church of the Foursquare Gospel | 347,367 | 1,844 | 726 | 92,275 | 399 | 82 | 36.2% | 27.6% | 12.7% |
| International Churches of Christ | 79,161 | 99 | 99 | New to Study in 2000 | New to Study in 2000 | ||||
| International Council of Community Churches | 64,186 | 192 | 118 | New to Study in 2000 | New to Study in 2000 | ||||
| International Pentecostal Church of Christ | 5,453 | 67 | 49 | 1,351 | (11) | (5) | 32.9% | -14.1% | -9.3% |
| International Pentecostal Holiness Church | 241,828 | 1,843 | 627 | 84,100 | 353 | 27 | 53.3% | 23.7% | 4.5% |
| Interstate & Foreign Landmark Missionary Baptists Association | 16,127 | 121 | 30 | (2,166) | (8) | (3) | -11.8% | -6.2% | -9.1% |
| Jain | 92 | 71 | New to Study in 2000 | New to Study in 2000 | |||||
| Jasper Baptist and Pleasant Valley Baptist Associations | 7,078 | 31 | 5 | (2,131) | (9) | (3) | -23.1% | -22.5% | -37.5% |
| Jewish Estimate | 6,141,325 | 3,727 | 672 | 158,796 | (248) | (197) | 2.7% | -6.2% | -22.7% |
| Landmark Missionary Baptists, Independent Associations and Unaffiliated Churches | 5,682 | 59 | 31 | New to Study in 2000 | New to Study in 2000 | ||||
| Lutheran Church--Missouri Synod | 2,521,062 | 6,077 | 1,801 | (82,663) | 57 | (7) | -3.2% | 0.9% | -0.4% |
| Macedonian Orthodox Church: American Diocese | 16,640 | 17 | 17 | New to Study in 2000 | New to Study in 2000 | ||||
| Malankara Archdiocese of the Syrian Orthodox Church in North America | 4,336 | 24 | 18 | New to Study in 2000 | New to Study in 2000 | ||||
| Malankara Orthodox Syrian Church, American Diocese of the | 13,225 | 59 | 35 | New to Study in 2000 | New to Study in 2000 | ||||
| Mennonite Brethren Churches, U.S. Conference of | 28,142 | 171 | 82 | 6,045 | 37 | (12) | 27.4% | 27.6% | -12.8% |
| Mennonite Church USA | 156,345 | 1,066 | 400 | (38,865) | (433) | (144) | -19.9% | -28.9% | -26.5% |
| Mennonite; Other Groups | 34,617 | 412 | 237 | New to Study in 2000 | New to Study in 2000 | ||||
| Midwest Congregational Christian Fellowship | 1,705 | 29 | 8 | (175) | (1) | (1) | -9.3% | -3.3% | -11.1% |
| Missionary Church, The | 49,528 | 284 | 136 | 9,580 | (19) | (13) | 24.0% | -6.3% | -8.7% |
| Moravian Church in America--Alaska Province | 2,562 | 24 | 3 | (2,776) | 2 | - | -52.0% | 9.1% | 0.0% |
| Moravian Church in America--Northern Province | 25,872 | 93 | 44 | (5,378) | (5) | (5) | -17.2% | -5.1% | -10.2% |
| Moravian Church in America--Southern Province | 19,764 | 59 | 19 | (1,505) | 4 | (1) | -7.1% | 7.3% | -5.0% |
| Muslim Estimate | 1,559,294 | 1,209 | 424 | New to Study in 2000 | New to Study in 2000 | ||||
| National Association of Congregational Christian Churches | 84,380 | 426 | 232 | (14,730) | 27 | (23) | -14.9% | 6.8% | -9.0% |
| National Association of Free Will Baptists | 254,170 | 2,466 | 710 | (39,278) | 5 | 32 | -13.4% | 0.2% | 4.7% |
| National Primitive Baptist Convention, USA | 66,452 | 547 | 147 | New to Study in 2000 | New to Study in 2000 | ||||
| Netherlands Reformed Congregations | 4,442 | 15 | 13 | (727) | - | - | -14.1% | 0.0% | 0.0% |
| New Hope Baptist Association | 2,772 | 20 | 6 | (378) | (2) | (1) | -12.0% | -9.1% | -14.3% |
| New Testament Association of Independent Baptist Churches and other Fundamental Baptist Associations/Fellowships | 132,684 | 649 | 314 | New to Study in 2000 | New to Study in 2000 | ||||
| North American Baptist Conference | 59,545 | 290 | 167 | 5,535 | 23 | (13) | 10.2% | 8.6% | -7.2% |
| "Old" Missionary Baptists Associations | 49,870 | 302 | 85 | 33,581 | 229 | 65 | 206.2% | 313.7% | 325.0% |
| Old Order Amish Church | 96,986 | 1,290 | 238 | (24,764) | 460 | 57 | -20.3% | 55.4% | 31.5% |
| Old Order Mennonite | 21,116 | 132 | 51 | New to Study in 2000 | New to Study in 2000 | ||||
| Old Order River Brethren | 540 | 5 | 3 | 26 | (2) | (1) | 5.1% | -28.6% | -25.0% |
| Original Free Will Baptists | 46,211 | 237 | 38 | New to Study in 2000 | New to Study in 2000 | ||||
| Orthodox Church in America: Albanian Orthodox Archdiocese | 5,775 | 12 | 9 | NA | (1) | (1) | NA | -7.7% | -10.0% |
| Orthodox Church in America: Bulgarian Diocese | 8,791 | 18 | 15 | New to Study in 2000 | New to Study in 2000 | ||||
| Orthodox Church in America: Romanian Orthodox Episcopate of America | 17,201 | 56 | 45 | NA | 13 | 10 | NA | 30.2% | 28.6% |
| Orthodox Church in America: Territorial Dioceses | 77,110 | 370 | 226 | NA | (56) | (13) | NA | -13.1% | -5.4% |
| Orthodox Presbyterian Church, The | 26,346 | 278 | 217 | New to Study in 2000 | NA | NA | 0.0% | ||
| Patriarchal Parishes of the Russian Orthodox Church in the USA | 32 | 29 | New to Study in 2000 | New to Study in 2000 | |||||
| Pentecostal Church of God | 101,921 | 1,173 | 574 | 10,849 | 2 | 2 | 11.9% | 0.2% | 0.3% |
| Presbyterian Church (U.S.A.) | 3,141,566 | 11,106 | 2,377 | (411,769) | (327) | (56) | -11.6% | -2.9% | -2.3% |
| Presbyterian Church in America | 315,293 | 1,441 | 631 | 93,901 | 280 | 58 | 42.4% | 24.1% | 10.1% |
| Primitive Baptist Churches--Old Line | 1,381 | 713 | New to Study in 2000 | New to Study in 2000 | |||||
| Primitive Baptists, Eastern District Association of | 7,840 | 67 | 15 | New to Study in 2000 | New to Study in 2000 | ||||
| Primitive Methodist Church in the USA | 4,796 | 79 | 35 | (3,141) | (2) | (3) | -39.6% | -2.5% | -7.9% |
| Progressive Primitive Baptists | 9,615 | 121 | 71 | New to Study in 2000 | New to Study in 2000 | ||||
| Protestant Reformed Churches in America | 5,875 | 26 | 15 | New to Study in 2000 | NA | NA | 0.0% | ||
| Reformed Baptist Churches | 197 | 167 | New to Study in 2000 | New to Study in 2000 | |||||
| Reformed Church in America | 335,677 | 896 | 237 | (27,255) | (21) | (6) | -7.5% | -2.3% | -2.5% |
| Reformed Church in the United States | 4,236 | 38 | 35 | 514 | 3 | 4 | 13.8% | 8.6% | 12.9% |
| Reformed Mennonite Church | 347 | 9 | 9 | New to Study in 2000 | New to Study in 2000 | ||||
| Romanian Orthodox Archdiocese in America and Canada | 7,543 | 14 | 12 | New to Study in 2000 | NA | NA | 0.0% | ||
| Russian Orthodox Church Outside of Russia | 129 | 101 | New to Study in 2000 | New to Study in 2000 | |||||
| Salvation Army, The | 415,060 | 1,332 | 818 | 287,483 | 165 | 14 | 225.3% | 14.1% | 1.7% |
| Separate Baptists in Christ | 10,674 | 94 | 35 | New to Study in 2000 | NA | NA | 0.0% | ||
| Serbian Orthodox Church in the USA | 55,807 | 75 | 61 | New to Study in 2000 | New to Study in 2000 | ||||
| Serbian Orthodox Church in the USA (New Gracanica Metropolitanate) | 38 | 32 | New to Study in 2000 | New to Study in 2000 | |||||
| Seventh-day Adventist Church | 923,046 | 4,507 | 1,747 | 19,984 | 293 | (167) | 2.2% | 7.0% | -8.7% |
| Sikh | 211 | 118 | New to Study in 2000 | New to Study in 2000 | |||||
| Southern Baptist Convention | 19,881,467 | 41,514 | 2,670 | 940,785 | 3,592 | 112 | 5.0% | 9.5% | 4.4% |
| Southwide Baptist Fellowship | 501 | 327 | New to Study in 2000 | New to Study in 2000 | |||||
| Strict Baptists | 33 | 3 | 3 | New to Study in 2000 | New to Study in 2000 | ||||
| Syrian Orthodox Church of Antioch | 13,845 | 23 | 19 | (16,155) | (6) | (3) | -53.9% | -20.7% | -13.6% |
| Tao | 38 | 24 | New to Study in 2000 | New to Study in 2000 | |||||
| Two-Seed-in-the-Spirit Predestinarian Baptists | 65 | 4 | 4 | (22) | 1 | 1 | -25.3% | 33.3% | 33.3% |
| Ukrainian Orthodox Church of the USA | 35,586 | 104 | 77 | NA | 81 | 50 | NA | 352.2% | 185.2% |
| Unitarian Universalist Association of Congregations | 182,698 | 999 | 593 | (7,495) | 34 | (16) | -3.9% | 3.5% | -2.6% |
| United Church of Christ | 1,698,918 | 5,863 | 1,229 | (294,541) | (397) | (97) | -14.8% | -6.3% | -7.3% |
| United Methodist Church, The | 10,350,629 | 35,721 | 3,003 | (740,403) | (1,517) | 26 | -6.7% | -4.1% | 0.9% |
| United Reformed Churches in North America | 11,449 | 49 | 34 | New to Study in 2000 | New to Study in 2000 | ||||
| Universal Fellowship of Metropolitan Community Churches | 23,440 | 206 | 179 | New to Study in 2000 | NA | NA | 0.0% | ||
| Vineyard USA | 155,170 | 529 | 339 | New to Study in 2000 | New to Study in 2000 | ||||
| Wayne Trail Missionary Baptist Association | 2,756 | 13 | 9 | 289 | 2 | - | 11.7% | 18.2% | 0.0% |
| Wesleyan Church, The | 381,459 | 1,657 | 766 | 121,719 | - | (25) | 46.9% | 0.0% | -3.2% |
| Wisconsin Evangelical Lutheran Synod | 405,078 | 1,277 | 535 | (14,850) | 49 | 5 | -3.5% | 4.0% | 0.9% |
| Zoroastrian | 35 | 26 | New to Study in 2000 | New to Study in 2000 | |||||