Wasco County is one of the 36 counties in the U.S. state of Oregon. As of the 2020 census, the population was 25,213. Its county seat is The Dalles. The county is named for a local tribe of Native Americans, the Wasco, a Chinook tribe who live on the south side of the Columbia River. It is near the Washington state line. Wasco County comprises The Dalles Micropolitan Statistical Area.

Celilo Falls on the Columbia River served as a gathering place and major trading center for the local Native Americans, including the Wasco, Paiute, and Warm Springs tribes, for thousands of years. These rapids came to be named Les Grandes Dalles de la Columbia or "The Great Falls of the Columbia" by the French Canadian fur traders.

The Dalles initially served as a way station on the Oregon Trail as it approached the Willamette Valley. The construction of the Barlow Road over the Cascade Range in 1845, and the Donation Land Claim Act of 1850 encouraged families to settle in the area. Over the following years, Wasco County was a major transportation hub for both river and inland traffic.

The Oregon Territorial Legislature created Wasco County on January 11, 1854, from the parts of Clackamas, Lane, Linn and Marion counties, that were east of the Cascade Range. At the time of its creation, it was the largest county in the United States, consisting of 130,000 square miles (340,000 km) that stretched clear to the Rocky Mountains. Its northern border was the Washington Territory line (the Columbia River). When Dakota Territory (including present-day Wyoming) was created in 1861, Idaho Territory in 1863, and Montana Territory in 1864, the parts of Wasco County east of the present Oregon boundaries were ceded to those territories. Other Oregon counties were split away, and Wasco was reduced to its current size.

Dates of Secession of Other Eastern Oregon Counties
County	Secession Date
Baker	1862
Umatilla	1862
Grant	1864
Lake	1874
Crook	1882
Morrow	1884
Gilliam	1885
Sherman	1889
Hood River	1908

The Dalles was designated the county seat with the creation of the county, and has been its only location.

The river traffic on the Columbia River was profoundly affected in 1935 by the building of Bonneville Dam in Multnomah County and by The Dalles Dam in 1957 in Wasco County (which submerged Celilo Falls).

Wasco County attracted international attention in the 1980s, when Bhagwan Shree Rajneesh established the Rajneeshpuram movement at a marginal ranch originally called "The Big Muddy". Disagreements with the county government and other residents over zoning rules and building codes escalated, while his followers, known as Rajneeshees, settled en bloc in Antelope, Oregon and were able to elect a majority of the town councillors. When the Rajneeshees subsequently recruited homeless people from across the United States to settle at Rajneeshpuram, it was widely seen as an attempt to use the ballot box to seize control of the county. An intentional outbreak of salmonella in salad bars at ten restaurants in The Dalles in 1984 was traced to the acts of Rajneeshees.

Rajneesh was arrested as he was fleeing the U.S. in 1985 and he was subsequently indicted along with seven followers for immigration crimes by a federal grand jury. A separate grand jury in Wasco County charged three Rajneeshees of attempted murder, while Rajneesh entered an Alford plea and was given a suspended sentence on condition that he leave the country.

The former Rajneesh ranch is now known as "Washington Family Ranch". It is owned and operated by Young Life Ministries, a Christian organization providing camp services for youth.

According to the United States Census Bureau, the county has a total area of 2,395 square miles (6,200 km), of which 2,382 square miles (6,170 km) is land and 14 square miles (36 km) (0.6%) is water. The northern boundary with Washington is the Columbia River (the state line).

• Mount Hood National Forest

Historical population

Census	Pop.	Note	%±
1860	1,689		—
1870	2,509		48.5%
1880	11,120		343.2%
1890	9,183		−17.4%
1900	13,199		43.7%
1910	16,336		23.8%
1920	13,648		−16.5%
1930	12,646		−7.3%
1940	13,069		3.3%
1950	15,552		19.0%
1960	20,205		29.9%
1970	20,133		−0.4%
1980	21,732		7.9%
1990	21,683		−0.2%
2000	23,791		9.7%
2010	25,213		6.0%
2020	26,670		5.8%
2023 (est.)	26,333		−1.3%
U.S. Decennial Census 1790–1960 1900–1990 1990–2000 2010–2020

As of the 2010 census, there were 25,213 people, 10,031 households, and 6,540 families living in the county. The population density was 10.6 inhabitants per square mile (4.1/km). There were 11,487 housing units at an average density of 4.8 units per square mile (1.9 units/km). The racial makeup of the county was 86.1% white, 4.4% American Indian, 0.8% Asian, 0.6% Pacific islander, 0.4% black or African American, 5.2% from other races, and 2.5% from two or more races. Those of Hispanic or Latino origin made up 14.8% of the population. In terms of ancestry, 19.8% were German, 14.0% were English, 10.6% were Irish, 6.4% were American, and 5.0% were Swedish.

Of the 10,031 households, 29.3% had children under the age of 18 living with them, 49.4% were married couples living together, 10.9% had a female householder with no husband present, 34.8% were non-families, and 28.8% of households were made up of individuals. The average household size was 2.44 and the average family size was 2.98. The median age was 41.7 years.

The median household income was $42,133 and the median family income was $50,279. Males had a median income of $40,658 versus $27,996 for females. The per capita income for the county was $21,922. About 11.1% of families and 15.5% of the population were below the poverty line, including 20.1% of those under age 18 and 7.6% of those age 65 or over.

As of the 2000 census, there were 23,791 people, 9,401 households, and 6,505 families living in the county. The population density was 10 people per square mile (3.9 people/km). There were 10,651 housing units at an average density of 4 units per square mile (1.5/km). The racial makeup of the county was 86.58% White, 3.81% Native American, 0.80% Asian, 0.50% Pacific Islander, 0.30% Black or African American, 5.65% from other races, and 2.36% from two or more races. 9.31% of the population were Hispanic or Latino of any race. 17.8% were of German, 11.8% English, 9.8% American, 9.5% Irish and 5.0% Norwegian ancestry of the 9,401 households 30.20% had children under the age of 18 living with them, 54.80% were married couples living together, 9.90% had a female householder with no husband present, and 30.80% were non-families. 26.10% of households were one person and 11.50% were one person aged 65 or older. The average household size was 2.47 and the average family size was 2.96.

The age distribution was 25.40% under the age of 18, 7.40% from 18 to 24, 25.20% from 25 to 44, 25.40% from 45 to 64, and 16.70% 65 or older. The median age was 40 years. For every 100 females there were 97.90 males. For every 100 females age 18 and over, there were 95.10 males.

The median household income was $35,959 and the median family income was $42,412. Males had a median income of $36,051 versus $21,575 for females. The per capita income for the county was $17,195. About 10.30% of families and 12.90% of the population were below the poverty line, including 17.70% of those under age 18 and 7.30% of those age 65 or over.

The Northern Oregon Regional Corrections Facility (Norcor), a short-term jail, serves Wasco, Gilliam, Hood River, and Sherman counties.

Politically, Wasco is a swing county. No presidential candidate has won more than 55% of the county's vote since Ronald Reagan in 1984. From 1972 to 2008, it voted for the election's national winner every time except the drought and farm crisis-influenced 1988 election; Obama lost here by just 18 votes or 0.2% of the popular vote in 2012.

Wasco County is currently one of 11 counties in Oregon in which therapeutic psilocybin is legal.

United States presidential election results for Wasco County, Oregon

Year	Republican		Democratic		Third party(ies)
	No.	%	No.	%	No.	%
2024	6,837	51.06%	6,069	45.32%	485	3.62%
2020	7,035	49.79%	6,604	46.74%	491	3.47%
2016	5,833	48.75%	4,781	39.96%	1,350	11.28%
2012	5,229	48.09%	5,211	47.93%	433	3.98%
2008	5,103	44.84%	5,906	51.90%	371	3.26%
2004	6,119	50.98%	5,691	47.42%	192	1.60%
2000	5,356	50.23%	4,616	43.29%	692	6.49%
1996	3,662	36.80%	4,967	49.91%	1,323	13.29%
1992	3,242	29.55%	4,663	42.50%	3,068	27.96%
1988	4,462	45.37%	5,141	52.28%	231	2.35%
1984	6,905	55.36%	5,526	44.31%	41	0.33%
1980	4,703	45.95%	4,336	42.36%	1,196	11.69%
1976	4,258	46.08%	4,560	49.35%	422	4.57%
1972	4,537	51.70%	3,749	42.72%	489	5.57%
1968	3,842	46.26%	3,918	47.17%	546	6.57%
1964	2,695	31.35%	5,890	68.51%	12	0.14%
1960	4,355	49.58%	4,426	50.39%	3	0.03%
1956	4,332	50.98%	4,165	49.02%	0	0.00%
1952	4,362	63.09%	2,517	36.40%	35	0.51%
1948	2,740	51.74%	2,438	46.03%	118	2.23%
1944	2,429	50.75%	2,313	48.33%	44	0.92%
1940	2,553	45.79%	3,001	53.82%	22	0.39%
1936	1,278	24.65%	3,573	68.92%	333	6.42%
1932	1,740	37.31%	2,776	59.52%	148	3.17%
1928	2,746	60.85%	1,699	37.65%	68	1.51%
1924	2,409	51.46%	1,185	25.32%	1,087	23.22%
1920	2,698	62.25%	1,434	33.09%	202	4.66%
1916	2,243	47.53%	2,287	48.46%	189	4.01%
1912	775	29.88%	929	35.81%	890	34.31%
1908	1,309	57.14%	764	33.35%	218	9.52%
1904	2,092	67.33%	536	17.25%	479	15.42%

The county's economy is based upon agriculture (orchards, wheat farming, livestock ranching), lumber, manufacturing, electric power, transportation, and tourism. Aluminum production was previously a major support of the local economy, but electrical price fluctuations and a slump in global aluminum prices has forced the closing of a number of local aluminum foundries.

• Antelope, previously known as Rajneesh
• Dufur
• Maupin
• Mosier
• Shaniko
• The Dalles (county seat)

• Chenoweth
• Pine Grove
• Pine Hollow
• Rowena
• Sportsmans Park
• Tygh Valley
• Wamic

• National Register of Historic Places listings in Wasco County, Oregon
• 1984 Rajneeshee bioterror attack

• Bruce Harris, The Wasco County History Book. The Dalles, OR: Bruce Harris, 1983.
• John Lundell, Governmental history of Wasco County, Oregon. n.c: n.p., 1970.
• William H. McNeal, History of Wasco County, Oregon. The Dalles, OR: William H. McNeal, 1953.
• Rodger Nichols and Dan Spatz, A Sesquicentennial History of Wasco County. The Dalles, OR: Dalles Chronicle, 2004.
• An Illustrated History of Central Oregon, Embracing Wasco, Sherman, Gilliam, Wheeler, Crook, Lake, and Klamath Counties, State of Oregon. Spokane, WA: Western Historical Publishing Co., 1905.

• Wasco County Home Page

45°10′N 121°10′W / 45.16°N 121.16°W / 45.16; -121.16