​​The individual county histories trace the establishment and evolution of each county government in Oregon. This include information about the creation and naming of the county; designation of county boundaries; location of the county seat; construction of the county courthouse; development of the county government; and description of industrial geographical, demographic, or historical features.

Select a county or use the cli​ckable map below.

Baker | Benton | Clacka​mas ​| Clatsop ​​| Columbia | Coos | Crook | Curry | Deschutes | Douglas | Gilliam ​| Grant​ | Harney | Hood River | Jackson | Jefferson | Josephine | Klamath​ | Lak​e​ | Lane​​ | Lincoln​ | Linn​ | Malheur​| Marion​| Morrow​ | Multnomah​| P​olk​ | Sherman​ | Tillamook​​ | Umatilla | Union​ | Wallowa​ | Wasco​ | Washington​ | Wheeler ​| Yamhill​​