| Name of County
|
Date Formed
|
Parent County
|
Progeny County
|
| Baker
|
22 Sep 1862
|
Wasco
|
Malheur 1887, Union 1864
|
| Benton
|
23 Dec 1847
|
Polk
|
Lincoln 1893, Umpqua 1851
|
| Champoeg
|
05 Jul 1843
|
Oregon Country
|
Linn 1847, renamed Marion 1849
|
| Clackamas
|
05 Jul 1843
|
Oregon Country
|
Multnomah 1854, Wasco 1854
|
| Clark
|
05 Jul 1843
|
Oregon Country
|
now in Washington State
|
| Clatsop
|
22 Jun 1844
|
Twality
|
Tillamook 1853
|
| Columbia
|
16 Jan 1854
|
Washington
|
none
|
| Coos
|
22 Dec 1853
|
Umpqua, Jackson
|
Curry 1855
|
| Crook
|
24 Oct 1882
|
Wasco
|
Deschutes 1916, Jefferson 1914, Wheeler 1899
|
| Curry
|
18 dec 1855
|
Coos
|
none
|
| Deschutes
|
13 Dec 1916
|
Crook
|
none
|
| Douglas
|
07 Jan 1852
|
Umpqua
|
Wasco 1854
|
| Gilliam
|
25 Feb 1885
|
Wasco
|
Wheeler 1899
|
| Grant
|
14 Oct 1864
|
Wasco, Umatilla
|
Harney 1889, Wheeler 1899
|
| Harney
|
23 Feb1 889
|
Grant
|
none
|
| Hood River
|
23 Jun 1908
|
Wasco
|
none
|
| Jackson
|
12 Jan 1852
|
Umpqua
|
Coos 1853, Josephine 1856, Lake 1874, Wasco 1854
|
| Jefferson
|
12 Dec 1914
|
Crook
|
none
|
| Josephine
|
22 Jan 1856
|
Jackson
|
none
|
| Klamath
|
17 Oct 1882
|
Lake
|
none
|
| Lake
|
24 Oct 1874
|
Jackson, Wasco
|
Klamath 1882
|
| Lane
|
28 Jan 1851
|
Linn, Umpqua
|
Wasco 1854
|
| Lewis
|
09 Dec 1845
|
Oregon Country
|
now in Washington State
|
| Lincoln
|
20 Feb 1893
|
Benton, Polk
|
none
|
| Linn
|
28 Dec 1847
|
Champoeg
|
Lane 1851, Umpqua 1851, Wasco 1854
|
| Malheur
|
17 Feb 1887
|
Baker
|
none
|
| Marion
|
03 Sep 1849
|
renamed from Champoeg
|
Wasco 1854
|
| Morrow
|
16 Feb 1885
|
Umatilla
|
none
|
| Multnomah
|
22 Dec 1854
|
Washington, Clackamas
|
none
|
| Polk
|
22 Dec 1845
|
Yamhill
|
Benton 1847, Lincoln 1893, Tillamook 1853
|
| Sherman
|
25 Feb 1889
|
Wasco
|
none
|
| Tillamook
|
15 Dec 1853
|
Clatsop, Polk, Yamhill
|
none
|
| Twality
|
05 Jul 1843
|
Oregon Country
|
renamed Washington 1845
|
| Umatilla
|
27 Sep 1862
|
Wasco
|
Grant 1864, Morrow 1885
|
| Umpqua
|
28 Jan 1851
|
Benton, Linn
|
Coos 1853, Douglas 1852, Jackson 1852, Lane 1851, dissolved into Douglas 1863
|
| Union
|
14 Oct 1864
|
Baker
|
Wallowa 1887, Baker 1901
|
| Wallowa
|
11 Feb 1887
|
Union
|
none
|
| Wasco
|
11 Jan 1854
|
Clackamas, Marion, Linn, Lane, Douglas
|
Baker 1862, Crook 1882, Gilliam 1855, Grant 1864, Hood River 1908, Lake 1874, Sherman 1889, Umatilla 1862
|
| Washington
|
22 Dec 1845
|
renamed from Twality
|
Columbia 1854, Multnomah 1854
|
| Wheeler
|
17 Feb 1899
|
Crook, Gilliam, Grant
|
none
|
| Yamhill
|
05 Jul 1843
|
Oregon Country
|
Polk 1845, Tillamook 1853
|