| Name of County | Date Formed | Boundary Changes | Parent County | Counties Created by Boundary Changes |
| Anderson | 1801 Nov 06 | Details | Knox | divided to Campbell 1806, Scott 1849, Union 1797 |
| Bedford | 1807 Dec 03 | Details | Rutherford | Coffee 1836, Franklin 1807, Lincoln 1809, Marshall 1836, Moore 1817 |
| Benton | 1835 Dec 19 | Details | Henry, Humphreys | none |
| Bledsoe | 1807 Nov 30 | Details | Roane | Cumberland 1855, Van Buren 1840 |
| Blount | 1795 Jul 11 | Details | Knox | Christiana 1870, Roane 1801 |
| Bradley | 1836 Feb 10 | Details | Indian lands | Polk 1839 |
| Campbell | 1806 Sep 11 | Details | Anderson, Claiborne | Union 1797 |
| Cannon | 1836 Jan 31 | Details | Coffee, Warren, Wilson | DeKalb 1837 |
| Carroll | 1821 Nov 07 | Details | Western District | none |
| Carter | 1796 Apr 09 | Details | Washington | Johnson 1836, Unicoi 1875 |
| Cheatham | 1856 Feb 28 | Details | Davidson, Dickson, Montgomery | none |
| Chester | 1875 Mar 04 | Details | Hardeman, Henderson, Madison, McNairy | none |
| Christiana | 1870 Jun 02 | Details | Blount, Monroe, McMinn, Roane | renamed Loudon 1870 |
| Claiborne | 1801 Oct 29 | Details | Grainger, Hawkins | Hancock 1844, Union 1797 |
| Clay | 1870 Jun 24 | Details | Jackson, Overton | none |
| Cocke | 1797 Oct 09 | Details | Anderson, Campbell, Claiborne, Grainger, Knox | none |
| Crockett | 1845 Dec 20 | Details | Dyer, Madison, Gibson, Haywood | none |
| Cumberland | 1855 Nov 16 | Details | Bledsoe, Morgan, Roane | none |
| Davidson | 1783 Apr 18 | Details | Washington | Cheatham 1856, Rutherford 1803, Sumner 1786, Williamson 1799 |
| Decatur | 1845 18 No | Details | Perry | none |
| DeKalb | 1837 Dec 11 | Details | Cannon, Warren, White | Putnam 1842 |
| Dickson | 1803 Oct 25 | Details | Montgomery, Robertson | Cheatham 1856, Hickman 1807, Houston 1871 |
| Dyer | 1823 Oct 16 | Details | Western District | Crockett 1845, Lauderdale 1835 |
| Fayette | 1824 Sep 29 | Details | Shelby, Hardeman | none |
| Fentress | 1823 Nov 28 | Details | Morgan, Overton | Pickett 1874, Scott 1849 |
| Franklin | 1807 Dec 03 | Details | Bedford, Warren | Coffee 1836, Moore 1817 |
| Gibson | 1823 Oct 21 | Details | Western District | Crockett 1845 |
| Giles | 1809 Nov 14 | Details | Maury | none |
| Grainger | 1796 Apr 22 | Details | Hawkins, Knox | Claiborne 1801, Hamblen 1870, Union 1797 |
| Greene | 1783 Apr 18 | Details | Washington | Jefferson 1792, Knox 1792 |
| Grundy | 1844 Jan 29 | Details | Coffee, Warren | none |
| Hamblen | 1870 Jun 08 | Details | Grainger, Hawkins | none |
| Hamilton | 1819 Oct 25 | Details | Rhea | Meigs 1836, Sequatchie 1857 |
| Hancock | 1844 Jan 07 | Details | Claibrone, Hawkins | none |
| Hardeman | 1823 Oct 16 | Details | Western District | Chester 1875, Fayette 1824 |
| Hardin | 1819 Nov 13 | Details | Western District | McNairy 1823, Shelby 1819 |
| Hawkins | 1786 Nov 18 | Details | Sullivan | Claiborne 1801, Grainger 1795, Knox 1792, Hamblen 1870, Hancock 1844, Jefferson 1792 |
| Haywood | 1823 Nov 03 | Details | Western District | Crockett 1845 |
| Henderson | 1821 Nov 07 | Details | Western District | Chester 1875 |
| Henry | 1821 Nov 07 | Details | Western District | Benton 1835 |
| Hickman | 1807 Dec 03 | Details | Dickson | Lawrence 1817, Lewis 1843, Perry 1821, Wayne 1817 |
| Houston | 1871 Jan 23 | Details | Dickson, Stewart | none |
| Humphreys | 1809 Oct 19 | Details | Steward, Smith | Benton 1835 |
| Jackson | 1801 Nov 06 | Details | Smith | Clay 1870, Overton 1806, Putnam 1842, White 1806 |
| Jefferson | 1792 Jun 11 | Details | Greene, Hawkins | Cocke 1797, Sevier 1794 |
| Johnson | 1836 Jan 02 | Details | Carter | none |
| Knox | 1792 Jun 11 | Details | Greene, Hawkins | Anderson 1801, Bledsoe 1807, Blount 1795, Grainger 1796, Roane 1801, Union 1797 |
| Lake | 1870 Jun 24 | Details | Obion | none |
| Lauderdale | 1835 Nov 24 | Details | Dyer, Tipton | none |
| Lawrence | 1817 Oct 21 | Details | Hickman, Maury | Lewis 1843 |
| Lewis | 1843 Dec 21 | Details | Hickman, Lawrence, Maury, Wayne | none |
| Lincoln | 1809 Nov 14 | Details | Bedford | Marshall 1836 |
| Loudon | 1870 Jun 02 | Details | renamed from Christiana | none |
| Macon | 1842 Jan 18 | Details | Smith, Sumner | Trousdale 1870 |
| Madison | 1821 Nov 07 | Details | Western District | Chester 1875, Crockett 1845 |
| Marion | 1817 Nov 20 | Details | Indian lands | none |
| Marshall | 1836 Feb 20 | Details | Bedford, Giles, Lincoln, Maury | none |
| Maury | 1807 Nov 16 | Details | Williamson | Giles 1809, Lawrence 1817, Lewis 1843 |
| McMinn | 1819 Nov 13 | Details | Indian lands | Christiana 1870, Meigs 1836, Polk 1839 |
| McNairy | 1823 Oct 08 | Details | Hardin | Chester 1875 |
| Meigs | 1836 Jan 20 | Details | Hamilton, McMinn, Rhea | none |
| Monroe | 1819 Nov 13 | Details | Roane | Christiana 1870 |
| Montgomery | 1796 Apr 09 | Details | State of Tennessee | Cheatham 1856, Dixon 1803, Stewart 1803 |
| Moore | 1817 Dec 14 | Details | Bedford, Franklin | none |
| Morgan | 1817 Oct 15 | Details | Roane | Cumberland 1855, Fentress 1823, Scott 1849 |
| Obion | 1823 Oct 24 | Details | Western District | Lake 1870 |
| Overton | 1806 Sep 11 | Details | Jackson | Clay 1870, Fentress 1823, Pickett 1879, Putnam 1842, White 1806 |
| Perry | 1821 Nov 14 | Details | Hickman | Decatur 1845 |
| Pickett | 1879 Feb 27 | Details | Fentress, Overton | none |
| Polk | 1839 Nov 28 | Details | Bradley, McMinn | none |
| Putnam | 1842 Feb 02 | Details | DeKalb, Jackson, Overton, White | none |
| Rhea | 1807 Nov 30 | Details | Roane | Hamilton 1819, Meigs 1836 |
| Roane | 1801 Nov 06 | Details | Knox, Blount | Bledsoe 1807, Christiana 1870, Rhea 1807, Cumberland 1855, Monroe 1819, Morgan 1817 |
| Robertson | 1796 Apr 09 | Details | State of Tennessee | Dixon 1803 |
| Rutherford | 1803 Oct 25 | Details | Davidson | Bedford 1807 |
| Scott | 1849 Dec 17 | Details | Fentress, Morgan, Anderson | none |
| Sequatchie | 1857 Dec 09 | Details | Hamilton | none |
| Sevier | 1794 Sep 27 | Details | Jefferson | none |
| Shelby | 1819 Nov 24 | Details | Hardin | Fayette 1824 |
| Smith | 1799 Oct 26 | Details | Sumner | Humphreys 1809, Jackson 1801, Macon 1842, Trousdale 1870, White 1806 |
| Stewart | 1803 Nov 01 | Details | Montgomery | Houston 1871, Humphreys 1809 |
| Sullivan | 1779 Oct 18 | Details | Washington | Hawkins 1786 |
| Sumner | 1786 Nov 18 | Details | Davidson | Macon 1842, Smith 1799, Wilson 1799 |
| Tipton | 1823 Oct 29 | Details | Western District | Lauderdale 1835 |
| Trousdale | 1870 Jun 21 | Details | Macon, Smith, Wilson | none |
| Unicoi | 1875 Mar 23 | Details | Washington | none |
| Union | 1797 Oct 09 | Details | Anderson, Campbell, Claiborne, Grainger, Knox | none |
| Van Buren | 1840 Jan 03 | BUREN Details | Bledsoe, Warren, White | none |
| Warren | 1807 Nov 26 | Details | White | Cannon 1836, Coffee 1836, DeKalb 1837, Franklin 1807, Grundy 1844, Van Buren 1840 |
| Washington | 1777 Nov 15 | Details | colonial lands | Carter 1796, Davidson 1783, Greene 1783, Sullivan 1779, Unicoi 1875 |
| Wayne (old) | 1785 5 17 | Details | colonial lands | abolished 1788 |
| Wayne (new) | 1817 Nov 24 | Details | Hickman | Lewis 1843 |
| Weakley | 1823 Oct 21 | Details | Western District | none |
| White | 1806 Sep 11 | Details | Overton, Jackson, Smith | DeKalb 1837, Putnam 1842, Van Buren 1840, Warren 1807 |
| Williamson | 1799 Oct 26 | Details | Davidson | Maury 1807 |
| Wilson | 1799 Oct 26 | Details | Sumner | Trousdale 1870 |