Baker County	001	Baker City	1862	Wasco County, Union County and Malheur County	Edward Dickinson Baker, a senator from Oregon who was killed at Ball's Bluff, a battle of the American Civil War	16,510	3,068 sq mi
(7,946 km2)	State map highlighting Baker County
Benton County	003	Corvallis	1847	Polk County	Thomas Hart Benton (1782.1858), a U.S. senator who advocated U.S. control over the Oregon Country	91,320	676 sq mi
(1,751 km2)	State map highlighting Benton County
Clackamas County	005	Oregon City	1843	One of the original four districts of the Oregon Country	The Clackamas Indians, a Native American tribe living in the area.	404,980	1,868 sq mi
(4,838 km2)	State map highlighting Clackamas County
Clatsop County	007	Astoria	1844	Northern and western portions of the original Twality District	Clatsop tribe of Native Americans, who lived along the coast of the Pacific Ocean prior to European settlement	38,225	827 sq mi
(2,142 km2)	State map highlighting Clatsop County
Columbia County	009	Saint Helens	1854	Northern half of Washington County	Columbia River, which forms the county's northern borders	50,795	657 sq mi
(1,702 km2)	State map highlighting Columbia County
Coos County	011	Coquille	1853	Western parts of Umpqua and Jackson Counties	The Coos Tribe of Native Americans who lived in the region	63,190	1,600 sq mi
(4,144 km2)	State map highlighting Coos County
Crook County	013	Prineville	1882	Southern part of Wasco County	George Crook (1828.1890), a U.S. Army officer who served in the American Civil War and the Indian Wars	21,580	2,980 sq mi
(7,718 km2)	State map highlighting Crook County
Curry County	015	Gold Beach	1855	Coos County	George Law Curry (1820.1878), a governor of the Oregon Territory	22,600	1,627 sq mi
(4,214 km2)	State map highlighting Curry County
Deschutes County	017	Bend	1916	Southern part of Crook County	"Riviere des Chutes", French for "River of the Falls".	176,635	3,018 sq mi
(7,817 km2)	State map highlighting Deschutes County
Douglas County	019	Roseburg	1852	Portion of Umpqua County which lay east of the Coast Range summit	Stephen A. Douglas (1813.1861), a U.S. Senator who supported Oregon statehood	110,395	5,037 sq mi
(13,046 km2)	State map highlighting Douglas County
Gilliam County	021	Condon	1885	Eastern third of Wasco County	Cornelius Gilliam (1798.1848), a pioneer who commanded the forces of the Provisional Government of Oregon after the Whitman Massacre	1,980	1,204 sq mi
(3,118 km2)	State map highlighting Gilliam County
Grant County	023	Canyon City	1864	Parts of old Wasco and old Umatilla counties	Ulysses S. Grant (1822.1885), army officer who served in the Oregon Territory; a Union general in the American Civil War at the time of the county's creation; and subsequently President of the United States (1869.1877)	7,410	4,529 sq mi
(11,730 km2)	State map highlighting Grant County
Harney County	025	Burns	1889	Southern two-thirds of Grant County	William S. Harney (1800.1889), a cavalry officer of the period, who was involved in the Pig War	7,320	10,135 sq mi
(26,250 km2)	State map highlighting Harney County
Hood River County	027	Hood River	1908	Northwest portion of Wasco County	The Hood River (a tributary of the Columbia River), which flows through the county	24,735	522 sq mi
(1,352 km2)	State map highlighting Hood River County
Jackson County	029	Medford	1852	Southwestern portion of Lane County and the unorganized area south of Douglas and Umpqua Counties	Andrew Jackson (1767.1845), the seventh President of the United States	213,765	2,785 sq mi
(7,213 km2)	State map highlighting Jackson County
Jefferson County	031	Madras	1914	Crook County	Mount Jefferson, which is located on its western boundary, named in turn for Thomas Jefferson (1743.1826), the 3rd president of the United States.	22,790	1,781 sq mi
(4,613 km2)	State map highlighting Jefferson County
Josephine County	033	Grants Pass	1856	Western half of Jackson County	Virginia "Josephine" Rollins, the first white woman to make this county her home.	84,675	1,640 sq mi
(4,248 km2)	State map highlighting Josephine County
Klamath County	035	Klamath Falls	1882	Western part of Lake County	The Klamath or Clamitte tribe, which has had a presence in the area for 10,000 years.	67,410	5,945 sq mi
(15,397 km2)	State map highlighting Klamath County
Lake County	037	Lakeview	1874	Jackson and Wasco Counties	Numerous lakes and hot springs.	8,015	7,940 sq mi
(20,565 km2)	State map highlighting Lake County
Lane County	039	Eugene	1851	Southern part of Linn County and the portion of Benton County east of Umpqua County	Gen. Joseph Lane (1801.1881), the first governor of Oregon Territory	365,940	4,554 sq mi
(11,795 km2)	State map highlighting Lane County
Lincoln County	041	Newport	1893	Western portion of Benton County and Polk County	Abraham Lincoln (1809.1865), sixteenth President of the United States.	47,735	980 sq mi
(2,538 km2)	State map highlighting Lincoln County
Linn County	043	Albany	1847	Southern portion of Champoeg (later Marion) County	U.S. Senator Lewis F. Linn (1795.1843) of Missouri, author of the Donation Land Act, which provided free land to settlers in the West.	122,315	2,291 sq mi
(5,934 km2)	State map highlighting Linn County
Malheur County	045	Vale	1887	Southern portion of Baker County	Malheur River (formally "Riviere au Malheur" or "Unfortunate River"), named by French trappers whose property and furs were stolen from their river encampment.	31,705	9,888 sq mi
(25,610 km2)	State map highlighting Malheur County
Marion County	047	Salem	1843	One of the original four districts of the Oregon territory	Francis Marion (1732.1795), American Revolutionary War general	333,950	1,185 sq mi
(3,069 km2)	State map highlighting Marion County
Morrow County	049	Heppner	1885	Western portion of Umatilla County and a small portion of eastern Wasco County	Jackson L. Morrow, a state representative who advocated for the formation of the county.	11,745	2,033 sq mi
(5,265 km2)	State map highlighting Morrow County
Multnomah County	051	Portland	1854	Eastern part of Washington and the northern part of Clackamas counties	The Indian village of Multnomah, on Sauvie Island. The word is derived from nematlnomaq, probably meaning downriver. Lewis and Clark made note of the name in 1805, and applied that name to all local Indians.	790,670	435 sq mi
(1,127 km2)	State map highlighting Multnomah County
Polk County	053	Dallas	1845	Yamhill District	James Knox Polk (1795.1849), President of the United States at the time of the county's creation	79,730	741 sq mi
(1,919 km2)	State map highlighting Polk County
Sherman County	055	Moro	1889	Northeast corner of Wasco County	William Tecumseh Sherman (1820.1891), American Civil War general, and businessman, educator, and author	1,795	823 sq mi
(2,132 km2)	State map highlighting Sherman County
Tillamook County	057	Tillamook	1853	Clatsop, Yamhill and Polk Counties	Tillamook (or Killamook) Native American people.	25,920	1,102 sq mi
(2,854 km2)	State map highlighting Tillamook County
Umatilla County	059	Pendleton	1862	Portion of Wasco County	Sahaptin word, possibly meaning laughing waters.	79,880	3,215 sq mi
(8,327 km2)	State map highlighting Umatilla County
Union County	061	La Grande	1864	Baker County	The town of Union, which had been established two years before and named by its founders for the "Union" of the states during the Civil War.	26,745	2,037 sq mi
(5,276 km2)	State map highlighting Union County
Wallowa County	063	Enterprise	1887	Eastern portion of Union County.	The Nez Perce word wallowa to designate a tripod of poles used to support fish nets. The area was claimed by the Chief Joseph band of the Nez Perce as its hunting and fishing grounds	7,140	3,145 sq mi
(8,146 km2)	State map highlighting Wallowa County
Wasco County	065	The Dalles	1854	Parts of Clackamas, Lane, Linn and Marion counties	The Wasco (or Wascopam) Native American tribe.	26,700	2,381 sq mi
(6,167 km2)	State map highlighting Wasco County
Washington County	067	Hillsboro	1843	One of the original four districts of the Oregon Country (as Twality District)	George Washington (1732.1799), Founding Father of the United States and first President of the United States	583,595	724 sq mi
(1,875 km2)	State map highlighting Washington County
Wheeler County	069	Fossil	1899	Parts of Grant, Gilliam, and Crook Counties	Henry H. Wheeler, who operated the first mail stage line from The Dalles to Canyon City.	1,465	1,715 sq mi
(4,442 km2)	State map highlighting Wheeler County
Yamhill County	071	McMinnville	1843	One of the original four districts of the Oregon Country	The Yamhelas, members of the Kalapuya Native American family, who lived along the Yamhill River in the western Willamette Valley.	104,990	716 sq mi
(1,854 km2)	State map highlighting Yamhill County