Cassia County, Idaho Population 2026
Updated April 2026 · US Census ACS 2023 5-Year Estimates · 15th-largest in Idaho
The population of Cassia County, Idaho is 25,165 as of the 2023 American Community Survey, making it the 15th-largest county in Idaho. The median household income is $67,042, the median home value is $257,300, and the median age is 33.1.
The population of Cassia County has grown 12.5% since 2010 (23,080 → 25,976), a +0.85% annualized rate.
25,165
Population
+0.85%
Annual growth
10
People / sq mi
$67,042
Median Income
$257,300
Median Home Value
Cassia County covers 2,566 sq mi of land at 9.8 people per square mile.
About Cassia County, ID
Cassia County is a county in Idaho with a population of 25,165. It ranks #15 among counties in Idaho by population. The median age is 33.1, younger than the national median. The population is 51.4% male and 48.6% female.
The median household income in Cassia County is $67,042, below the US median of $74,580. 6.8% of residents live below the federal poverty level. Home values sit at a median of $257,300, with monthly rent averaging $920. The homeownership rate of 70.0% is higher than the national rate of 64.8%.
Educational attainment in Cassia County reflects 20.9% of adults 25 and older holding a bachelor's degree or higher, below the national average of 34.3%. Roughly 7.7% of workers primarily work from home, below the national work-from-home rate of 14.2%. The average commute is 17.8 minutes each way.
Cassia County Population History (2010-2024)
The county of Cassia County had a population of 23,080 in 2010 and 25,976 in 2024, a 12.5% growth over 14 years. The peak was 25,976 in 2024. Average annual growth rate: 0.85%.
25,976
Population (2024)
23,080
Population (2010)
25,976
Peak (2024)
0.85%
Avg Annual Growth
| Year | Population |
|---|---|
| 2010 | 23,080 |
| 2011 | 23,111 |
| 2012 | 23,265 |
| 2013 | 23,344 |
| 2014 | 23,503 |
| 2015 | 23,497 |
| 2016 | 23,477 |
| 2017 | 23,661 |
| 2018 | 23,769 |
| 2019 | 24,052 |
| 2020 | 24,755 |
| 2021 | 25,242 |
| 2022 | 25,625 |
| 2023 | 25,817 |
| 2024 | 25,976 |
Race & Ethnicity
| White | 72.3% |
| Black or African American | 0.1% |
| Asian | 0.0% |
| Hispanic or Latino (any race) | 3.5% |
| Two or More Races | 0.0% |
Age & Sex
33.1
Median Age
48.6%
Female
51.4%
Male
13.7%
Age 65+
Age Distribution
Children (under 15): 25.5% · Seniors (65+): 13.7%
Income & Poverty
| Median household income | $67,042$-7,594 vs state |
| Mean household income | $88,788 |
| Per-capita income | $30,688 |
| Poverty rate | 6.8%-0.2% vs state |
| Unemployment rate | 1.7% |
| Employment-to-population | 64.4% |
Top Industries by Employment
The largest employment sector in Cassia County is professional & business services, accounting for 17.6% of workers.
How residents commute
0.2%
Drive alone
1.3%
Carpool
81.3%
Public transit
7.7%
Work from home
17.8 min
Avg commute
Housing
$257,300$-118,700 vs state
Median home value
$920
Median rent
70.0%
Homeownership rate
8,992
Total housing units
91.6%
Occupied
8.4%
Vacant
30.0%
Renter-occupied
Social & access
88.5%
With health insurance
93.3%
With broadband internet
30.9%
Foreign-born
4.4%
Veterans (18+)
13.5%
With a disability
78.9%
Speak language other than English at home
Education
85.4%
High School+
20.9%
Bachelor's+
Largest cities in Idaho
Other counties in Idaho
Part of Idaho
Metro areas in Idaho
County rankings
Frequently Asked Questions
Cassia County, Idaho has a population of 25,165 according to the US Census Bureau's 2023 American Community Survey 5-year estimates, making it the 15th-largest county in Idaho. Population density is 10 people per square mile.
The population of Cassia County has grown 12.5% since 2010 (23,080 → 25,976), a +0.85% annualized rate.
The median household income in Cassia County, Idaho is $67,042, with mean (average) household income of $88,788 and per-capita income of $30,688. 6.8% of residents live below the federal poverty level.
In Cassia County, the largest racial and ethnic groups are White (72.3%), Hispanic or Latino (3.5%), Black or African American (0.1%). Figures are from the US Census Bureau's 2023 ACS 5-year estimates and reflect self-reported responses.
The median age in Cassia County, Idaho is 33.1 years. Residents are 48.6% female and 51.4% male.
The median home value in Cassia County is $257,300 and median monthly rent is $920. 70.0% of occupied housing units are owner-occupied. The county has 8,992 total housing units, 8.4% of which are vacant.
The largest employment sector in Cassia County, Idaho is professional, scientific, and management services, employing 17.6% of workers. The unemployment rate is 1.7%.
Boise City is among the largest cities associated with Cassia County, Idaho, with a population of 235,701.
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Statewide data for Idaho
Population, race, income, age, and trends across Idaho
Data from the American Community Survey (ACS) 5-Year estimates.
Source: U.S. Census Bureau ACS, 2026.