Lewis County, Idaho Population 2026
Updated April 2026 · US Census ACS 2023 5-Year Estimates · 41st-largest in Idaho
The population of Lewis County, Idaho is 3,649 as of the 2023 American Community Survey, making it the 41st-largest county in Idaho. The median household income is $49,643, the median home value is $202,400, and the median age is 48.9.
The population of Lewis County has declined 2.4% since 2010 (3,820 → 3,728), a -0.17% annualized rate.
3,649
Population
-0.17%
Annual growth
8
People / sq mi
$49,643
Median Income
$202,400
Median Home Value
Lewis County covers 479 sq mi of land at 7.6 people per square mile.
About Lewis County, ID
Lewis County skews on age — the median resident is 48.9, older than the national median. Lewis County is a county in Idaho with a population of 3,649. It ranks #41 among counties in Idaho by population.
Incomes run on the lower side: a median household income of $49,643, below the US median of $78,538. The poverty rate is 12.3%, close to the national 12.4%. The typical home is valued at $202,400, with typical rent around $708.
20.0% of adults 25 and older hold a bachelor’s degree, below the national average of 35.0%. About 10.7% of workers primarily work from home, below the national 14.0%, and the average commute runs about 21 minutes each way.
The age structure shapes everything downstream in Lewis County — from housing demand to the mix of working-age earners reflected in the income figures above.
Lewis County Population History (2010-2024)
The county of Lewis County had a population of 3,820 in 2010 and 3,728 in 2024, a -2.4% growth over 14 years. The peak was 3,883 in 2017. Average annual growth rate: -0.14%.
3,728
Population (2024)
3,820
Population (2010)
3,883
Peak (2017)
-0.14%
Avg Annual Growth
| Year | Population |
|---|---|
| 2010 | 3,820 |
| 2011 | 3,805 |
| 2012 | 3,820 |
| 2013 | 3,805 |
| 2014 | 3,813 |
| 2015 | 3,792 |
| 2016 | 3,850 |
| 2017 | 3,883 |
| 2018 | 3,835 |
| 2019 | 3,845 |
| 2020 | 3,524 |
| 2021 | 3,689 |
| 2022 | 3,727 |
| 2023 | 3,740 |
| 2024 | 3,728 |
Race & Ethnicity
| White | 83.4% |
| Black or African American | 1.7% |
| Asian | 0.0% |
| Hispanic or Latino (any race) | 6.1% |
| Two or More Races | 0.0% |
Age & Sex
48.9
Median Age
50.0%
Female
50.0%
Male
27.8%
Age 65+
Age Distribution
Children (under 15): 17.9% · Seniors (65+): 27.8%
Income & Poverty
| Median household income | $49,643$-24,993 vs state |
| Mean household income | $69,631 |
| Per-capita income | $29,737 |
| Poverty rate | 12.3%+5.3% vs state |
| Unemployment rate | 1.6% |
| Employment-to-population | 45.4% |
Top Industries by Employment
The largest employment sector in Lewis County is professional & business services, accounting for 23.4% of workers.
How residents commute
0.0%
Drive alone
3.1%
Carpool
74.9%
Public transit
10.7%
Work from home
20.8 min
Avg commute
Housing
$202,400$-173,600 vs state
Median home value
$708
Median rent
74.2%
Homeownership rate
1,823
Total housing units
84.8%
Occupied
15.2%
Vacant
25.8%
Renter-occupied
Social & access
87.5%
With health insurance
87.2%
With broadband internet
47.3%
Foreign-born
10.5%
Veterans (18+)
24.8%
With a disability
95.9%
Speak language other than English at home
Education
90.8%
High School+
20.0%
Bachelor's+
Largest cities in Idaho
Other counties in Idaho
Part of Idaho
Metro areas in Idaho
County rankings
Frequently Asked Questions
Lewis County, Idaho has a population of 3,649 according to the US Census Bureau's 2023 American Community Survey 5-year estimates, making it the 41st-largest county in Idaho. Population density is 8 people per square mile.
The population of Lewis County has declined 2.4% since 2010 (3,820 → 3,728), a -0.17% annualized rate.
The median household income in Lewis County, Idaho is $49,643, with mean (average) household income of $69,631 and per-capita income of $29,737. 12.3% of residents live below the federal poverty level.
In Lewis County, the largest racial and ethnic groups are White (83.4%), Hispanic or Latino (6.1%), Black or African American (1.7%). Figures are from the US Census Bureau's 2023 ACS 5-year estimates and reflect self-reported responses.
The median age in Lewis County, Idaho is 48.9 years. Residents are 50.0% female and 50.0% male.
The median home value in Lewis County is $202,400 and median monthly rent is $708. 74.2% of occupied housing units are owner-occupied. The county has 1,823 total housing units, 15.2% of which are vacant.
The largest employment sector in Lewis County, Idaho is professional, scientific, and management services, employing 23.4% of workers. The unemployment rate is 1.6%.
Boise City is among the largest cities associated with Lewis County, Idaho, with a population of 235,701.
Lewis County, ID Climate
Lewis County, ID has an average annual temperature of 6.8°C (44°F) and receives about 642 mm of precipitation per year. The warmest month is August and the coldest is January. Figures are 1970–2000 climate normals.
6.8°C
Avg Temp
642
Precip (mm/yr)
Aug
Hottest Month
Jan
Coldest Month
| Month | Avg (°C/°F) | Precip |
|---|---|---|
| January | -3° / 27° | 63 mm |
| February | 0° / 31° | 47 mm |
| March | 2° / 36° | 59 mm |
| April | 6° / 42° | 62 mm |
| May | 10° / 50° | 75 mm |
| June | 13° / 56° | 62 mm |
| July | 17° / 62° | 27 mm |
| August | 18° / 64° | 34 mm |
| September | 13° / 55° | 41 mm |
| October | 7° / 45° | 51 mm |
| November | 1° / 34° | 62 mm |
| December | -3° / 27° | 59 mm |
1970–2000 normals from WorldClim 2.1 (~9 km grid). Precipitation can be less precise near mountains or coastlines, where rainfall varies sharply over short distances.
Best time to visit Lewis County, ID
The most comfortable months to visit Lewis County, ID are typically August, July and September, when temperatures are mildest and rainfall is relatively low. The hottest month is August (around 28°C high). The coldest is January (near -7°C low). May is usually the wettest month.
Where to stay near Lewis County
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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.