Gem County, Idaho Population 2026
Updated April 2026 · US Census ACS 2023 5-Year Estimates · 19th-largest in Idaho
The population of Gem County, Idaho is 19,854 as of the 2023 American Community Survey, making it the 19th-largest county in Idaho. The median household income is $66,245, the median home value is $367,300, and the median age is 42.8.
The population of Gem County has grown 31.0% since 2010 (16,686 → 21,857), a +1.95% annualized rate.
19,854
Population
+1.95%
Annual growth
35
People / sq mi
$66,245
Median Income
$367,300
Median Home Value
Gem County covers 560 sq mi of land at 35.5 people per square mile.
About Gem County, ID
Gem County is a county in Idaho with a population of 19,854. It ranks #19 among counties in Idaho by population. The median age is 42.8, older than the national median. The population is 50.9% male and 49.1% female.
The median household income in Gem County is $66,245, below the US median of $74,580. 6.9% of residents live below the federal poverty level. Home values sit at a median of $367,300, with monthly rent averaging $887. The homeownership rate of 76.6% is higher than the national rate of 64.8%.
Educational attainment in Gem County reflects 22.3% of adults 25 and older holding a bachelor's degree or higher, below the national average of 34.3%. Roughly 12.6% of workers primarily work from home, similar to the national work-from-home rate of 14.2%. The average commute is 30.9 minutes each way.
Gem County Population History (2010-2024)
The county of Gem County had a population of 16,686 in 2010 and 21,857 in 2024, a 31.0% growth over 14 years. The peak was 21,857 in 2024. Average annual growth rate: 1.96%.
21,857
Population (2024)
16,686
Population (2010)
21,857
Peak (2024)
1.96%
Avg Annual Growth
| Year | Population |
|---|---|
| 2010 | 16,686 |
| 2011 | 16,696 |
| 2012 | 16,638 |
| 2013 | 16,582 |
| 2014 | 16,665 |
| 2015 | 16,706 |
| 2016 | 17,005 |
| 2017 | 17,351 |
| 2018 | 17,622 |
| 2019 | 18,174 |
| 2020 | 19,278 |
| 2021 | 19,813 |
| 2022 | 20,739 |
| 2023 | 21,384 |
| 2024 | 21,857 |
Race & Ethnicity
| White | 87.2% |
| Black or African American | 0.2% |
| Asian | 0.0% |
| Hispanic or Latino (any race) | 2.0% |
| Two or More Races | 0.0% |
Age & Sex
42.8
Median Age
49.1%
Female
50.9%
Male
22.7%
Age 65+
Age Distribution
Children (under 15): 18.4% · Seniors (65+): 22.7%
Income & Poverty
| Median household income | $66,245$-8,391 vs state |
| Mean household income | $87,429 |
| Per-capita income | $34,695 |
| Poverty rate | 6.9%-0.1% vs state |
| Unemployment rate | 1.6% |
| Employment-to-population | 55.6% |
Top Industries by Employment
The largest employment sector in Gem County is professional & business services, accounting for 21.5% of workers.
How residents commute
0.2%
Drive alone
1.4%
Carpool
75.3%
Public transit
12.6%
Work from home
30.9 min
Avg commute
Housing
$367,300$-8,700 vs state
Median home value
$887
Median rent
76.6%
Homeownership rate
7,788
Total housing units
95.1%
Occupied
4.9%
Vacant
23.4%
Renter-occupied
Social & access
88.1%
With health insurance
93.1%
With broadband internet
49.3%
Foreign-born
9.5%
Veterans (18+)
17.7%
With a disability
90.8%
Speak language other than English at home
Education
89.0%
High School+
22.3%
Bachelor's+
Largest cities in Idaho
Other counties in Idaho
Part of Idaho
Metro areas in Idaho
County rankings
Frequently Asked Questions
Gem County, Idaho has a population of 19,854 according to the US Census Bureau's 2023 American Community Survey 5-year estimates, making it the 19th-largest county in Idaho. Population density is 35 people per square mile.
The population of Gem County has grown 31.0% since 2010 (16,686 → 21,857), a +1.95% annualized rate.
The median household income in Gem County, Idaho is $66,245, with mean (average) household income of $87,429 and per-capita income of $34,695. 6.9% of residents live below the federal poverty level.
In Gem County, the largest racial and ethnic groups are White (87.2%), Hispanic or Latino (2.0%), Black or African American (0.2%). Figures are from the US Census Bureau's 2023 ACS 5-year estimates and reflect self-reported responses.
The median age in Gem County, Idaho is 42.8 years. Residents are 49.1% female and 50.9% male.
The median home value in Gem County is $367,300 and median monthly rent is $887. 76.6% of occupied housing units are owner-occupied. The county has 7,788 total housing units, 4.9% of which are vacant.
The largest employment sector in Gem County, Idaho is professional, scientific, and management services, employing 21.5% of workers. The unemployment rate is 1.6%.
Boise City is among the largest cities associated with Gem 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.