How many people live in Ada County, ID?
Updated Apr. 6, 2026Refreshed annually
In 2024, there were about 535,800 people living in Ada County, ID. That makes Ada County the most populous county in Idaho. It is home to 26.4% of people living in the state.
536K
population of Ada County, ID (2024)
26.4%
County share of the Idaho population (2024)
About 535,800 people lived in Ada County, ID in 2024.
Population estimates, 2000–2024
What are Ada County, ID’s age demographics?
About 92,600 Ada County, ID residents are aged 65 and older in 2024. That represents 17.3% of its population. For comparison, the age group represents 17.7% of Idaho’s population and 18% in the US overall.
Another 112,900 Ada County residents, or 21.1% 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 Ada County, ID's population is aged 25–44 than the US as a whole.
Population estimates by age group, (2024)
What are Ada County, ID’s racial and ethnic demographics?
Non-Hispanic white residents make up 81.4% of the Ada County, ID population, higher than the national share of 57.5%. Ada County, ID also has a larger share of people identifying as non-Hispanic two or more races (2.7%) than the US overall (2.5%).
In contrast, Ada County’s non-Hispanic Black or African American population accounts for 1.5%, below the 12.6% nationwide, and the Hispanic population makes up 10.4% of the county, compared with 20% 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.
Ada County, ID has a higher share of a non-Hispanic white population than Idaho as a whole.
Population estimates by race and ethnicity, (2024)
The largest city or town in Ada County, ID is Boise City with about 238,000 residents in 2024.
Cities and towns in Ada County, ID ranked by population
Population (2024), includes only portions within county
| City or town | Population | |
|---|---|---|
| 1. | Boise City | 237,963 |
| 2. | Meridian | 139,740 |
| 3. | Eagle | 33,451 |
| 4. | Kuna | 29,127 |
| 5. | Star (pt.) | 18,155 |
| 6. | Garden City | 12,936 |
| 7. | Balance of Ada County | 64,427 |
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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.
