History
The Governor of Washington Territory approved the proposed Adams County Articles of Incorporation on November 28, 1883. At that time Adams County and Franklin County were formed out of territory from Whitman County. The first County meeting (December 19, 1883) established Ritzville as the county seat. By 1885 the county offices were established, in a wood-frame house purchased for the purpose in Ritzville.
The 1890 census showed that Adams County boasted 2,098 residents. The growing population justified a purpose-built courthouse, so construction began on February 23, 1892, for a two-story brick building with a tower and a basement.
Wheat farming was a main focus of early residents. In 1909 Adams County proclaimed itself "bread basket of the world," with Ritzville reportedly being the world's largest inland wheat exporter.
1905 - "A number of officials also appeared before the board [of county commissioners] and asked that an addition be built to the courthouse for the accommodation of the auditor and treasurer who require more room on account of the increase in business." The architectural firm of Preusse and Zittel of Spokane began drawing plans for the proposed addition in March 1905. Adams County Commissioners (Joseph M. Batten, Henry J. Allert and Fred Kembel) approved the new addition in May 1905.
In 1905 the County courthouse was expanded. Work was completed in October 1905.
Wheat producers in Adams County used dryland farming in order to overcome the relative aridity of the county's climate. They let the wheatfields lie fallow in alternate years, holding sufficient moisture to raise profitable crops.
The county's population decreased significantly during the first half of the twentieth century, dropping by nearly five thousand from 1910 to 1940.
In 1940 the courthouse was replaced by a three-story building, with a two-story jail at the rear. Construction was completed in December 1940.
In 1943 the Federal government approved the Columbia Basin Project. It began impacting Adams County in 1946, when construction of the East Low Canal and the Potholes East Canal began. This work, and the ensuing increased agricultural production from irrigated crops, led to continual population increases. The population had increased by 12,500 from 1940 to 2010. [3]
Demographics
Historical population| Census | Pop. | Note | %± |
|---|
| 1890 | 2,098 | | — |
|---|
| 1900 | 4,840 | | 130.7% |
|---|
| 1910 | 10,920 | | 125.6% |
|---|
| 1920 | 9,623 | | −11.9% |
|---|
| 1930 | 7,719 | | −19.8% |
|---|
| 1940 | 6,209 | | −19.6% |
|---|
| 1950 | 6,584 | | 6.0% |
|---|
| 1960 | 9,929 | | 50.8% |
|---|
| 1970 | 12,014 | | 21.0% |
|---|
| 1980 | 13,267 | | 10.4% |
|---|
| 1990 | 13,603 | | 2.5% |
|---|
| 2000 | 16,428 | | 20.8% |
|---|
| 2010 | 18,728 | | 14.0% |
|---|
| 2020 | 20,613 | | 10.1% |
|---|
| 2023 (est.) | 20,820 | [5] | 1.0% |
|---|
|
Adams County and Franklin County have the highest per capita percentage of Latino residents in the state. [10] According to the 2020 Census, the Latino population of the county is 13,120 or 63.65% of residents. [11]
As of the first quarter of 2024, the median home value in Adams County was $239,530. [12]
As of the 2022 American Community Survey, there are 6,304 estimated households in Adams County with an average of 3.21 persons per household. The county has a median household income of $63,105. Approximately 14.6% of the county's population lives at or below the poverty line. Adams County has an estimated 62.3% employment rate, with 14.7% of the population holding a bachelor's degree or higher and 71.0% holding a high school diploma. [13]
The top five reported ancestries (people were allowed to report up to two ancestries, thus the figures will generally add to more than 100%) were English (48.9%), Spanish (48.9%), Indo-European (0.8%), Asian and Pacific Islander (0.5%), and Other (0.9%).
The median age in the county was 29.0 years.
Adams County, Washington – racial and ethnic composition
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 may be of any race.
| Race / ethnicity (NH = non-Hispanic) | Pop. 1980 | Pop. 1990 | Pop. 2000 [14] | Pop. 2010 [15] | Pop. 2020 [16] |
|---|
| White alone (NH) | 10,133
(76.38%) | 8,933
(65.67%) | 8,366
(50.93%) | 7,262
(38.78%) | 6,829
(33.13%) |
| Black or African American alone (NH) | 32
(0.24%) | 29
(0.21%) | 20
(0.12%) | 47
(0.25%) | 24
(0.12%) |
| Native American or Alaska Native alone (NH) | 61
(0.46%) | 64
(0.47%) | 45
(0.27%) | 76
(0.41%) | 63
(0.31%) |
| Asian alone (NH) | 70
(0.53%) | 90
(0.66%) | 75
(0.46%) | 99
(0.53%) | 129
(0.63%) |
| Pacific Islander alone (NH) | — | — | 2
(0.01%) | 3
(0.02%) | 3
(0.01%) |
| Other race alone (NH) | 18
(0.14%) | 20
(0.15%) | 9
(0.05%) | 18
(0.10%) | 87
(0.42%) |
| Mixed race or multiracial (NH) | — | — | 179
(1.09%) | 124
(0.66%) | 358
(1.74%) |
| Hispanic or Latino (any race) | 2,953
(22.26%) | 4,467
(32.84%) | 7,732
(47.07%) | 11,099
(59.26%) | 13,120
(63.65%) |
| Total | 13,267
(100.00%) | 13,603
(100.00%) | 16,428
(100.00%) | 18,728
(100.00%) | 20,613
(100.00%) |
2020 census
As of the 2020 census, there were 20,613 people, 6,228 households, and 4,794 families residing in the county. [17] The population density was 10.7 inhabitants per square mile (4.1/km2). There were 6,735 housing units at an average density of 3.5 inhabitants per square mile (1.4/km2). The racial makeup of the county was 44.46% White, 0.20% African American, 2.13% Native American, 0.65% Asian, 0.06% Pacific Islander, 35.35% from some other races and 17.15% from two or more races. Hispanic or Latino people of any race were 63.65% of the population. [18] 34.5% of residents were under the age of 18, 8.7% were under 5 years of age, and 12.2% were 65 and older.
2010 census
As of the 2010 census, there were 18,728 people, 5,720 households, and 4,410 families living in the county. The population density was 9.7 inhabitants per square mile (3.7/km2). There were 6,242 housing units at an average density of 3.2 inhabitants per square mile (1.2/km2). The racial makeup of the county was 62.49% White, 0.58% African American, 1.90% Native American, 0.67% Asian, 0.02% Pacific Islander, 31.50% from some other races and 2.84% from two or more races. Hispanic or Latino people of any race were 59.26% of the population.
In terms of ancestry, 16.4% were German, 6.8% were Irish, 5.6% were English, and 2.2% were American.
Of the 5,720 households, 47.9% had children under the age of 18 living with them, 58.7% were married couples living together, 11.8% had a female householder with no husband present, 22.9% were non-families, and 18.8% of all households were made up of individuals. The average household size was 3.25 and the average family size was 3.71. The median age was 29.0 years.
The median income for a household in the county was $40,829 and the median income for a family was $43,551. Males had a median income of $35,695 versus $25,160 for females. The per capita income for the county was $16,689. About 19.0% of families and 25.1% of the population were below the poverty line, including 36.6% of those under age 18 and 12.6% of those age 65 or over.
2000 census
As of the 2000 census, there were 16,428 people, 5,229 households, and 4,094 families living in the county. The population density was 8.0 inhabitants per square mile (3.1/km2). There were 5,773 housing units at an average density of 3.0 inhabitants per square mile (1.2/km2). The racial makeup of the county was 64.96% White, 0.28% African American, 0.68% Native American, 0.60% Asian, 0.04% Pacific Islander, 30.69% from some other races and 2.75% from two or more races. Hispanic or Latino people of any race were 47.07% of the population.
In terms of ancestry, 16.3% were of German, 6.2% identified as U.S. or American and 5.6% English ancestry. 57.0% spoke English, 41.7% Spanish and 1.2% German as their first language.
There were 5,229 households, out of which 44.00% had children under the age of 18 living with them, 63.50% were married couples living together, 10.10% had a female householder with no husband present, and 21.70% were non-families. 18.70% of all households were made up of individuals, and 7.70% had someone living alone who was 65 years of age or older. The average household size was 3.09 and the average family size was 3.52.
In the county, the population was spread out, with 34.20% under the age of 18, 9.80% from 18 to 24, 26.30% from 25 to 44, 19.40% from 45 to 64, and 10.40% who were 65 years of age or older. The median age was 30 years. For every 100 females there were 104.50 males. For every 100 females age 18 and over, there were 102.10 males.
The median income for a household in the county was $33,888, and the median income for a family was $37,075. Males had a median income of $28,740 versus $21,597 for females. The per capita income for the county was $13,534. About 13.60% of families and 18.20% of the population were below the poverty line, including 24.00% of those under age 18 and 8.90% of those age 65 or over.
United States
Washington 
