How many people live in Washington County, ID?
Updated Apr. 6, 2026Refreshed annually
In 2024, there were about 11,500 people living in Washington County, ID. That makes Washington County the 29th-most populous county in Idaho. It is home to 0.57% of people living in the state.
11.5K
population of Washington County, ID (2024)
0.57%
County share of the Idaho population (2024)
About 11,500 people lived in Washington County, ID in 2024.
Population estimates, 2000–2024
What are Washington County, ID’s age demographics?
About 3,000 Washington County residents are aged 65 and older in 2024. That represents 25.7% of its population. For comparison, the age group represents 17.7% of Idaho’s population and 18% in the US overall.
Another 2,500 Washington County, ID residents, or 21.6% of the population, were children under 18. For comparison, the age group represents 23.4% of Idaho’s population and 21.6% in the US overall.
A higher share of Washington County, ID's population is aged 65 or older than the US as a whole.
Population estimates by age group, (2024)
What are Washington County, ID’s racial and ethnic demographics?
Non-Hispanic white residents make up 77.3% of the Washington County, ID population, higher than the national share of 57.5%. Washington County, ID also has a larger share of people identifying as non-Hispanic American Indian and Alaska Native (0.98%) than the US overall (0.72%).
In contrast, Washington County’s non-Hispanic Black or African American population accounts for 0.64%, below the 12.6% nationwide, and the non-Hispanic Asian population makes up 0.89% of the county, compared with 6.5% nationally.
Racial and ethnic make up differ based on location. These figures reflect how people identified their race alone (not in combination with other races), and separate out Hispanic or Latino ethnicity, following Census reporting standards.
Washington County, ID has a higher share of a Hispanic population than Idaho as a whole.
Population estimates by race and ethnicity, (2024)
The largest city or town in Washington County, ID is Weiser with about 6,100 residents in 2024.
Cities and towns in Washington County, ID ranked by population
Population (2024), includes only portions within county
| City or town | Population | |
|---|---|---|
| 1. | Weiser | 6,112 |
| 2. | Cambridge | 365 |
| 3. | Midvale | 218 |
| 4. | Balance of Washington County | 4,844 |
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Methodology
USAFacts standardizes data, in areas such as time and demographics, to make it easier to understand and compare.
The analysis was generated with the help of AI and reviewed by USAFacts for accuracy.
Page sources
USAFacts endeavors to share the most up-to-date information available. We sourced the data on this page directly from government agencies; however, the intervals at which agencies publish updated data vary.
