Baker Formed: 1862 Parent: Wasco	Benton Formed: 1847 Parent: Polk	Clackamas Formed: 1843 Parent: [Original]	Clatsop Formed: 1844 Parent: Tuality	Columbia Formed: 1854 Parent: Washington
Coos Formed: 1853 Parent: Jackson/Umpqua	Crook Formed: 1882 Parent: Wasco	Curry Formed: 1855 Parent: Coos	Deschutes Formed: 1916 Parent: Crook	Douglas Formed: 1852 Parent: Umpqua
Gilliam Formed: 1885 Parent: Wasco/Morrow	Grant Formed: 1864 Parent: Umatilla/Wasco	Harney Formed: 1889 Parent: Grant	Hood River Formed: 1908 Parent: Wasco	Jackson Formed: 1852 Parent: Umpqua
Jefferson Formed: 1914 Parent: Crook	Josephine Formed: 1856 Parent: Jackson	Klamath Formed: 1882 Parent: Lake	Lake Formed: 1874 Parent: Jackson/Wasco	Lane Formed: 1851 Parent: Linn/Umpqua/Benton
Lincoln Formed: 1893 Parent: Benton/Polk	Linn Formed: 1847 Parent: Champoeg	Malheur Formed: 1887 Parent: Baker	Marion Formed: 1843 Parent: Champoeg	Morrow Formed: 1885 Parent: Umatilla
Multnomah Formed: 1854 Parent: Clackamas/Washington	Polk Formed: 1845 Parent: Yamhill	Sherman Formed: 1889 Parent: Wasco	Tillamook Formed: 1853 Parent: Clatsop/Yamhill/Polk	Umatilla Formed: 1862 Parent: Wasco
Umpqua Formed: 1851 Parent: Became part of	Union Formed: 1864 Parent: Baker	Wallowa Formed: 1887 Parent: Union	Wasco Formed: 1854 Parent: Marion/Clackamas/Linn	Washington Formed: 1843 Parent: Tuality

Wheeler Formed: 1899 Parent: Crook/Gilliam/Grant	Yamhill Formed: 1843 Parent: Original