• county
  • FIPS 16051
  • Largest town: Rigby

Jefferson County, Idaho

Jefferson County had 34,854 residents in the Census Vintage 2024 estimate, on 1,093.7 square miles of land. It ranks 12th of 44 in Idaho by population and 28th by land area.

Population
34,854
#12 of 44 in Idaho · #1,317 in US
Area
1,093.7 sq mi
#28 of 44 in Idaho · #584 in US
Density
32 / sq mi
#13 of 44 in Idaho · #1,868 in US
Median household income
$81,566
#5 of 44 in Idaho · #421 in US

Census Vintage 2024 estimates · SAIPE 2023 income · 2024 Gazetteer land area

Jefferson County within Idaho. Pin: Boise.

Measure from here

Tools and pages that start from Jefferson County

Jefferson County population, land area and income

Jefferson County had 34,854 residents in the Census Vintage 2024 estimate, on 1,093.7 square miles of land. It ranks 12th of 44 in Idaho by population and 28th by land area. That works out to 31.9 people per square mile, below the US average of 96.3, and below the national county median.

The median county-equivalent in Idaho has 15,019 residents, so Jefferson County is 2.3 times that size.

Its SAIPE 2023 median household income of $81,566 is in the top quarter among 3,143 counties with an estimate.

National rank among 3,144

Population

34,854

3144th1st

1317th of 3,144 (US)

Land area

1,094 sq mi

3144th1st

584th of 3,144 (US)

Density

31.9 / sq mi

3144th1st

1868th of 3,144 (US)

Median household income

$81,566

3143rd1st

421st of 3,143 (US)

Rank within Idaho (44)

Population

34,854

44th1st

12th of 44 (ID)

Land area

1,094 sq mi

44th1st

28th of 44 (ID)

Density

31.9 / sq mi

44th1st

13th of 44 (ID)

Median household income

$81,566

44th1st

5th of 44 (ID)

How Jefferson County's population changed since 2020

Jefferson County gained 3,772 residents between the July 2020 and July 2024 estimates, a rise of 12.1%. That ranks 7th of 44 in Idaho for growth. The median Idaho county changed by +7.2%, and the state as a whole by +8.2%.

Since the April 2020 estimates base, Jefferson County recorded 1,913 births and 979 deaths, a natural change of +934. Net international migration added +183 and net domestic migration, people moving to or from other US counties, came to +2,845. The largest single component was domestic migration, which added 2,845 people.

31.1k202032.2k202133.4k202234.3k202334.9k2024
Census Vintage 2024 county estimates for July 1 of each year. The axis starts above zero so year-to-year changes are visible.

Components of change, April 2020 to July 2024

Births
1,913
Deaths
979
Net international migration
+183
Net domestic migration
+2,845
Change, July 2023 to July 2024
+595

Where Jefferson County is

The Census internal point of Jefferson County is at 43.797000, -112.318600. It sits in UTM zone 12N. The map shades Idaho's 44 county-equivalents by population change from 2020 to 2024, darker for faster growth, with Jefferson County outlined. Dots are towns of 1,000+ people with residents in it.

Madison County: +5.0%Idaho County: +8.0%Benewah County: +9.9%Gooding County: +3.4%Lincoln County: +8.2%Minidoka County: +4.7%Custer County: +7.7%Boundary County: +15.6%Lemhi County: +5.5%Twin Falls County: +6.8%Franklin County: +9.5%Oneida County: +9.0%Gem County: +13.4%Shoshone County: +6.6%Fremont County: +7.3%Clearwater County: +4.6%Kootenai County: +9.0%Cassia County: +4.9%Blaine County: +3.8%Clark County: +0.1%Jerome County: +7.4%Bonner County: +13.8%Elmore County: +3.7%Caribou County: +3.2%Bonneville County: +7.1%Jefferson County: +12.1%Power County: +6.3%Lewis County: +5.8%Nez Perce County: +1.7%Ada County: +7.5%Adams County: +12.9%Valley County: +7.9%Bingham County: +5.8%Bannock County: +4.3%Owyhee County: +6.2%Washington County: +9.3%Latah County: +6.4%Teton County: +10.2%Camas County: +15.0%Boise County: +12.0%Bear Lake County: +6.5%Butte County: +5.9%Canyon County: +14.5%Payette County: +8.1%
Change 2020 to 2024
  1. < +4.7%
  2. < +6.4%
  3. < +7.7%
  4. < +9.9%
  5. ≥ +9.9%
no data

Orange pin: Jefferson County internal point. Dark pin: Boise.

Internal point

Decimal
43.797000, -112.318600
DMS
43°47'49.20"N 112°19'6.96"W
UTM
12N 393922.2E 4850171.4N
Geohash
9xb1hjh04
Plus code
85M9QMWJ+RH

Towns in Jefferson County

One incorporated place of 1,000+ people has residents in Jefferson County, 5,683 people together, or 16% of the county. Each figure counts only the part of the town inside Jefferson County; towns marked "part" extend into another county. The largest is Rigby with 5,683.

  1. 01Rigby5,683
Census Vintage 2024 subcounty estimates, county parts of incorporated places (SUMLEV 157).

Counties bordering Jefferson County

The Census 2024 county adjacency file lists 6 neighbors for Jefferson County. The most populous is Bonneville County, ID, with 133,644 residents. Distances run between Census internal points in a straight line.

Distance to Boise and the nearest big city

Boise is 195.0 miles W of Jefferson County's internal point in a straight line. The nearest place of 100,000 or more is Boise City, ID (population 237,963), 195.9 miles away. The nearest place of 10,000 or more is Idaho Falls, ID (population 69,523), 25.5 miles away.

Jefferson County FIPS code

The FIPS code of Jefferson County is 16051: state code 16 for Idaho plus county code 051. Use it as text, with the leading zero, when joining Census, BLS, or CDC county tables. SAIPE lists its 2023 median household income as $81,566.

Questions people ask

What is the population of Jefferson County, Idaho?

The Census Vintage 2024 estimate for July 1, 2024 is 34,854. That is up 3,772 people (12.1%) from the July 2020 estimate of 31,082.

What is the FIPS code of Jefferson County?

16051. The first two digits (16) are Idaho; the last three (051) identify the county.

What is the largest town in Jefferson County?

Rigby, with 5,683 residents inside Jefferson County in 2024.

Which counties border Jefferson County?

6 county-equivalents border it in the Census 2024 adjacency file: Bonneville County, ID; Madison County, ID; Bingham County, ID; Fremont County, ID; Butte County, ID; Clark County, ID.

Sources and data as of

Data as of: Census Vintage 2024 population estimates, 2024 Gazetteer land area and internal points, SAIPE 2023 median household income.

  1. 01Census Vintage 2024 county population estimates
  2. 02Census 2024 Gazetteer, counties
  3. 03Census SAIPE 2023 state and county estimates
  4. 04Census Vintage 2024 subcounty population estimates
  5. 05Census 2024 county adjacency file
  6. 06Census 2024 cartographic boundary file, counties (1:5,000,000)

How every number is computed: methodology. Spotted a wrong figure? Report an error.