Ada County, Idaho
Located in Idaho, Ada County has a population of 518,935 residents and a median age of 38.4 years, making it the #140 most populous county out of 3,222 nationwide. In terms of economic indicators, the county has a poverty rate of 8.3%. The median home value is $512,300, and the median household income is $91,502, which is 22% above the national median.
Demographics
Ada County has a population of 518,935, making it the #140 most populous county in the US. The median age is 38.4 years, which is 1.3% below the national median.
Population Trend
Rankings →Year-over-Year Population Growth
Age & Sex Distribution
Race & Ethnicity
Nativity
Geographic Mobility (Past Year)
Economy
The median household income in Ada County is $91,502, ranking #276 out of 3,222 counties — 21.8% above the national median. The poverty rate is 8.3% and unemployment stands at 3.1%.
Median Household Income Trend
Rankings →Income Distribution
Industry of Employment
Occupation
Housing
The median home value in Ada County is $512,300 (+81.7% vs national). Renters pay a median of $1,577/mo and the homeownership rate is 70.8%.
Median Home Value Trend
Rankings →Household Type
Education
In Ada County, 44.6% of adults age 25+ hold a bachelor's degree or higher, which is 32.3% above the national average, ranking #177 out of 3,222 counties.
Bachelor's Degree or Higher Trend
Rankings →Health & Wellbeing
Life expectancy in Ada County is 79.7 years. 12.9% of adults report poor or fair health and 7.1% lack health insurance. Data from County Health Rankings (2025).
Life Expectancy Trend
Substance Use
11.5% of adults in Ada County smoke , 28.7% are obese , and 19.5% report excessive drinking. The drug overdose death rate is 19.6 per 100,000.
Adult Smoking Trend
Safety
The homicide rate in Ada County is 1.3 per 100,000 and the suicide rate is 19.0 per 100,000. Motor vehicle deaths occur at a rate of 7.9 per 100,000.
Homicide Rate Trend
Families & Children
7.5% of children in Ada County live in poverty and the infant mortality rate is 4.6 per 1,000 live births. The teen birth rate is 7.9 per 1,000 females age 15–19.
Infant Mortality Trend
Civic & Transportation
Voter turnout in Ada County is 74.6%. The mean commute time is 23.2 min, which is 15.8% below the national average.
Voter Turnout Trend
Mean Commute Time Trend
Rankings →Elections
In the 2024 presidential election, Ada County voted Republican with a margin of 10.4%. The vote was 43.4% Dem / 53.8% Rep. Compared to 2020, the margin shifted 6.5 toward Republicans .
Vote Share Over Time
About Ada County, Idaho
Ada County, Idaho has a total population of 518,935, making it the 140th most populous county in the United States. The median age in Ada County is 38.4 years, which is 1.3% below the national median of 38.9 years.
The median household income in Ada County is $91,502, which ranks #276 of 3,222 counties nationwide. This is 21.8% above the national median of $75,149. The poverty rate is 8.3%, lower than the national rate of 12.6%. The unemployment rate stands at 3.1%.
The median home value in Ada County is $512,300, 81.7% above the national median. Renters in Ada County pay a median gross rent of $1,577 per month. The homeownership rate is 70.8%, compared to the national rate of 64.4%.
In Ada County, 44.6% of residents aged 25 and older hold a bachelor's degree or higher, 32.3% above the national average of 33.7%. Health insurance coverage stands at 93.6% of the population. The average commute time for workers is 23.2 min.
Ada County is a diverse community. The largest racial or ethnic group is White (non-Hispanic) at 80.9% of the population, followed by Hispanic or Latino (9.8%) and Two or More Races (4.3%).
All data for Ada County, Idaho comes from the U.S. Census Bureau's American Community Survey (ACS) 5-Year Estimates. These figures are estimates based on survey sampling and are subject to margin of error. For the most detailed and up-to-date data, visit the Census Bureau's official data portal.