County Maps US

Jefferson County, Idaho

A county in Idaho, ranked 12 of 44 by population.

CountyFIPS 16051

Within Idaho
Jefferson County, highlighted, with the areas around it. Boundaries generalised from the 2025 Census cartographic boundary file; neighbour fills carry no data. The dot marks Rigby, the county seat, located via the 2025 Census Gazetteer.

Download SVGFull Idaho map downloads

Population
35,297
+4,217 (+13.6%) since 2020
Land area
1,094
square miles. A further 1.1% of the total area is water
Population density
32.3
people per square mile, computed rather than published
County seat
Rigby
Seat of county government.
Established
1913
112 years ago
Largest city
Rigby city
Population 5,757.

Sources: US Census Bureau, Population Estimates Program, Vintage 2025 Population Estimates, released 26 March 2026; US Census Bureau, Gazetteer Files, 2025 Gazetteer Files, released 10 September 2025; Wikidata (CC0), Wikidata. Retrieved 30 August 2026.

Satellite view

Aerial imagery of Jefferson County with its boundary drawn on top. A map shows you the shape; this shows you what is inside it, and which side of the line a place falls on.

Aerial view of Jefferson County, Idaho from the USGS National Map, with its boundary outlined
Imagery: USGS National Map, USGS Imagery Only, public domain, requested from USGS by your browser when you reach this point on the page, at 800 by 488 pixels. The boundary is the 2025 Census cartographic boundary file, reprojected to Web Mercator to match the imagery. You can also open the USGS National Map viewer.

Where Jefferson County ranks

Position among the 44 counties of Idaho, and among all 3,144 US counties and county-equivalents. Computed from the figures on this page.

MeasureValueIn IdahoNationally
Population35,29712th of 441,306th of 3,144
Land area1,094 sq mi28th of 44584th of 3,144
Population density32.3 per sq mi13th of 441,858th of 3,144
Median household income$86,6794th of 44384th of 3,143

Full data for Jefferson County

Every figure below is attributed to the Census Bureau product it came from, with the vintage of that product.
MeasureValueSource and vintage
Population35,297Vintage 2025 Population Estimates
Population in 202031,080Vintage 2025 Population Estimates
2020 estimates base?30,891Vintage 2025 Population Estimates
Land area1,094 sq mi2025 Gazetteer Files
Water area12.0 sq mi2025 Gazetteer Files
Total area1,106 sq mi2025 Gazetteer Files
Population density?32.3 per sq miComputed: Vintage 2025 estimates divided by 2025 Gazetteer land area
Median household income$86,679American Community Survey 2020-2024 5-Year Estimates
Median home value$408,400American Community Survey 2020-2024 5-Year Estimates
Median age32.8American Community Survey 2020-2024 5-Year Estimates
Households10,199American Community Survey 2020-2024 5-Year Estimates
Housing units10,779American Community Survey 2020-2024 5-Year Estimates

Sources: US Census Bureau, Population Estimates Program, Vintage 2025 Population Estimates, released 26 March 2026; US Census Bureau, Gazetteer Files, 2025 Gazetteer Files, released 10 September 2025; US Census Bureau, American Community Survey, American Community Survey 2020-2024 5-Year Estimates, released 29 January 2026. Population density is computed here, not published: it divides the Vintage 2025 population estimate by the 2025 Gazetteer land area, which are two different Census products. Retrieved 30 August 2026.

How the population changed

The Census Bureau publishes the components behind an estimate, not just the total. For the year to July 2025:

Births minus deaths
+212
421 births, 209 deaths
Net migration
+228
More people moved in than moved out.

Source: US Census Bureau, Population Estimates Program, Vintage 2025 Population Estimates, released 26 March 2026. Retrieved 30 August 2026.

The 6 areas bordering Jefferson County

Ordered by the length of the border actually shared, which the Census Bureau publishes in its county adjacency file and which no other county reference presents.

Bordering areaStateShared borderPopulation
Bonneville CountyIdaho45 mi135,771
Madison CountyIdaho39 mi55,172
Clark CountyIdaho33 mi783
Butte CountyIdaho24 mi2,783
Fremont CountyIdaho18 mi14,208
Bingham CountyIdaho9.1 mi51,153

Source: US Census Bureau, County Adjacency File, 2025 County Adjacency File, released 15 September 2025. Retrieved 30 August 2026.

All 44 counties of Idaho

Open the interactive Idaho county map, or jump straight to any of them.

Data on this page last rebuilt 30 August 2026. How these figures are produced.