Baker County (1862 - Present)
Benton County (1847 - Present)
Champoeg County (1843 - Present)
Clackamas County (1843 - Present)
Clatsop County (1845 - Present)
Columbia County (1854 - Present)
Coos County (1853 - Present)
Crook County (1882 - Present)
Curry County (1855 - Present)
Deschutes County (1917 - Present)
Douglas County (1852 - Present)
Gilliam County (1885 - Present)
Grant County (1864 - Present)
Harney County (1889 - Present)
Hood River County (1908 - Present)
Jackson County (1852 - Present)
Jefferson County (1914 - Present)
Josephine County (1856 - Present)
Klamath County (1882 - Present)
Lake County (1874 - Present)
Lane County (1851 - Present)
Lewis Wa County (1845 - Present)
Lincoln County (1893 - Present)
Linn County (1847 - Present)
Malheur County (1887 - Present)
Morrow County (1885 - Present)
Multnomah County (1854 - Present)
Polk County (1845 - Present)
Sherman County (1889 - Present)
Tillamook County (1853 - Present)
Tuality County (1843 - Present)
Umatilla County (1862 - Present)
Umpqua County (1851 - 1863)
Umpqua County Proposed (1868 - 1868)
Union County (1864 - Present)
Wallowa County (1887 - Present)
Wasco County (1854 - Present)
Wheeler County (1899 - Present)
Yamhill County (1843 - Present)