# Washington County, Idaho

Washington County is a county in the U.S. state of Idaho. As of the 2020 census, the population was 10,500. The county seat and largest city is Weiser, with over half of the county's population. The county was established in 1879 when Idaho was a territory and named after U.S. President George Washington.

## Geography

According to the U.S. Census Bureau, the county has a total area of 1,474 square miles (3,820 km$^2$), of which 1,453 square miles (3,760 km$^2$) is land and 21 square miles (54 km$^2$) (1.4%) is water.

### Adjacent counties

* Adams County - north
* Gem County - east
* Payette County - south
* Malheur County, Oregon - southwest
* Baker County, Oregon - west

### Major highways

* US 95
* SH-71

### National protected areas

* Boise National Forest (part)
* Deer Flat National Wildlife Refuge (part)
* Payette National Forest (part)

### Rivers

* Snake River
* Weiser River

### Reservoirs

* Brownlee
* Crane Creek
* Mann Creek
* Paddock Valley

## Demographics
### 2020 census

As of the census of 2020, there were 10,500 people in 4,112 households living in the county. The population density was 7 people per square mile (2.7 people/km$^2$). There were 4,138 housing units at an average density of 3 units per square mile (1.2 units/km$^2$). The racial makeup of the county was 87.61% White, 1.03% Asian, 0.66% Native American, 0.10% Black or African American, 0.07% Pacific Islander, 8.17% from other races, and 2.36% from two or more races. 13.75% of the population were Hispanic or Latino of any race. 15.7% were of German, 14.3% English, 10.1% American and 7.7% Irish ancestry.
There were 3,762 households, out of which 32.7% had children under the age of 18 living with them, 60.7% were married couples living together, 8.2% had a female householder with no husband present, and 27.2% were non-families. 23.5% of all households were made up of individuals, and 13.30% had someone living alone who was 65 years of age or older. The average household size was 2.61 and the average family size was 3.10.
In the county, the population was spread out, with 27.4% under the age of 18, 7.20% from 18 to 24, 23.4% from 25 to 44, 24.3% from 45 to 64, and 17.70% who were 65 years of age or older. The median age was 39 years. For every 100 females there were 95.80 males. For every 100 females age 18 and over, there were 93.0 males.
The median income for a household in the county was $30,625, and the median income for a family was $35,542. Males had a median income of $27,222 versus $18,053 for females. The per capita income for the county was $15,464. About 10.00% of families and 13.30% of the population were below the poverty line, including 16.60% of those under age 18 and 9.90% of those age 65 or over.

### 2010 census

As of the 2010 United States census, there were 10,198 people, 4,034 households, and 2,803 families living in the county. The population density was 7.0 inhabitants per square mile (2.7/km$^2$). There were 4,529 housing units at an average density of 3.1 units per square mile (1.2 units/km$^2$). The racial makeup of the county was 86.6% white, 1.0% American Indian, 0.9% Asian, 0.2% black or African American, 9.1% from other races, and 2.2% from two or more races. Those of Hispanic or Latino origin made up 16.8% of the population. In terms of ancestry, 20.0% were English, 18.2% were German, 14.8% were Irish, and 9.6% were American.
Of the 4,034 households, 30.4% had children under the age of 18 living with them, 54.9% were married couples living together, 9.7% had a female householder with no husband present, 30.5% were non-families, and 25.8% of all households were made up of individuals. The average household size was 2.50 and the average family size was 2.99. The median age was 43.6 years.
The median income for a household in the county was $36,542 and the median income for a family was $46,970. Males had a median income of $36,765 versus $26,406 for females. The per capita income for the county was $20,015. About 10.9% of families and 13.2% of the population were below the poverty line, including 15.6% of those under age 18 and 9.6% of those age 65 or over.

### 2020 census

Note: the US Census treats Hispanic/Latino as an ethnic category. This table excludes Latinos from the racial categories and assigns them to a separate category. Hispanics/Latinos can be of any race.
Washington County racial composition (NH = Non-Hispanic) :
| Race | Pop 2010 | Pop 2020 | % 2010 | % 2020 |
| White (NH) | 8,166 | 8,118 | 80.07% | 77.31% |
| Black or African American (NH) | 10 | 17 | 0.1% | 0.16% |
| Native American or Alaska Native (NH) | 75 | 74 | 0.74% | 0.7% |
| Asian (NH) | 90 | 81 | 0.88% | 0.77% |
| Pacific Islander (NH) | 3 | 7 | 0.03% | 0.07% |
| Some Other Race (NH) | 12 | 53 | 0.12% | 0.5% |
| Mixed/Multi-Racial (NH) | 126 | 488 | 1.24% | 4.65% |
| Hispanic or Latino | 1,716 | 1,662 | 16.83% | 15.83% |
| Total | 10,198 | 10,500 | | |
As of the 2020 United States census, there were 10,500 people, 4,035 households, and 2,708 families residing in the county.

## Education

The county is served by three school districts based in the county:
* Weiser District #431
** Weiser High School
** Weiser Middle School
** Park Intermediate School
** Pioneer Primary School.
* Cambridge Joint District #432
** Cambridge Junior-Senior High School
** Cambridge Elementary School
* Midvale District #433
** Midvale Senior High School.
** Midvale Junior High School
** Midvale Elementary School
Additionally Payette Joint School District 371 includes a portion of Washington County.
Washington County is in the area (but not the taxing region) of the College of Western Idaho, which has its main campus in Nampa.

## Communities
### Cities

* Cambridge
* Midvale
* Weiser

## Politics

United States presidential election results for Washington County, Idaho :
| Year | Republican | Republican | Democratic | Democratic | Third party(ies) | Third party(ies) |
| Year | No. | % | No. | % | No. | % |
| 2024 | 4,429 | 79.73% | 1,010 | 18.18% | 116 | 2.09% |
| 2020 | 4,154 | 77.70% | 1,073 | 20.07% | 119 | 2.23% |
| 2016 | 3,283 | 73.69% | 776 | 17.42% | 396 | 8.89% |
| 2012 | 3,128 | 72.22% | 1,104 | 25.49% | 99 | 2.29% |
| 2008 | 3,168 | 70.31% | 1,241 | 27.54% | 97 | 2.15% |
| 2004 | 3,274 | 75.11% | 1,033 | 23.70% | 52 | 1.19% |
| 2000 | 2,899 | 71.23% | 980 | 24.08% | 191 | 4.69% |
| 1996 | 2,318 | 54.90% | 1,314 | 31.12% | 590 | 13.97% |
| 1992 | 1,802 | 42.09% | 1,122 | 26.21% | 1,357 | 31.70% |
| 1988 | 2,380 | 61.98% | 1,359 | 35.39% | 101 | 2.63% |
| 1984 | 3,015 | 71.99% | 1,119 | 26.72% | 54 | 1.29% |
| 1980 | 2,915 | 63.58% | 1,421 | 30.99% | 249 | 5.43% |
| 1976 | 2,044 | 53.47% | 1,693 | 44.28% | 86 | 2.25% |
| 1972 | 2,264 | 61.99% | 935 | 25.60% | 453 | 12.40% |
| 1968 | 2,020 | 57.65% | 1,033 | 29.48% | 451 | 12.87% |
| 1964 | 1,730 | 46.99% | 1,952 | 53.01% | 0 | 0.00% |
| 1960 | 2,251 | 55.86% | 1,779 | 44.14% | 0 | 0.00% |
| 1956 | 2,272 | 57.89% | 1,653 | 42.11% | 0 | 0.00% |
| 1952 | 2,616 | 64.91% | 1,411 | 35.01% | 3 | 0.07% |
| 1948 | 1,713 | 49.21% | 1,700 | 48.84% | 68 | 1.95% |
| 1944 | 2,002 | 51.95% | 1,849 | 47.98% | 3 | 0.08% |
| 1940 | 1,903 | 45.27% | 2,296 | 54.61% | 5 | 0.12% |
| 1936 | 1,234 | 34.70% | 2,147 | 60.38% | 175 | 4.92% |
| 1932 | 1,213 | 34.65% | 2,122 | 60.61% | 166 | 4.74% |
| 1928 | 1,973 | 66.39% | 974 | 32.77% | 25 | 0.84% |
| 1924 | 1,183 | 41.33% | 623 | 21.77% | 1,056 | 36.90% |
| 1920 | 1,864 | 59.59% | 1,264 | 40.41% | 0 | 0.00% |
| 1916 | 1,545 | 44.43% | 1,802 | 51.83% | 130 | 3.74% |
| 1912 | 724 | 25.32% | 1,065 | 37.25% | 1,070 | 37.43% |
| 1908 | 1,819 | 51.56% | 1,452 | 41.16% | 257 | 7.28% |
| 1904 | 1,894 | 60.69% | 931 | 29.83% | 296 | 9.48% |
| 1900 | 1,194 | 46.95% | 1,349 | 53.05% | 0 | 0.00% |

## Healthcare

The county is served by the Southwest Idaho Health District.