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Jefferson County, ID Demographics

Jefferson County, ID is the 12th most populous of 44 counties in Idaho, with 30,891 residents across 1,094 square miles. That is about 28 people per square mile.

At the 2020 census

Population 30,891
Land area 1,094 sq mi
Density 28 / sq mi

Data: 2020 Census · American Community Survey 2024

How Jefferson County compares to the US

We're computing this county's comparison table — check back shortly. Population, land area, and density above are already exact.

Central Location: Jefferson County, ID

Measured from the county's main population center using 2020 census blocks.

We're computing the drive-time and radius areas around Jefferson County, ID — check back shortly. Meanwhile you can drop a pin anywhere in the radius tool.

Census tracts in Jefferson County, ID

Name Population Sq mi Per sq mi
Census Tract 9604.02 7,003 50.7 138
Census Tract 9604.01 6,394 9.9 646
Census Tract 9603.02 6,001 5.5 1,082
Census Tract 9602 4,203 58.4 72
Census Tract 9601 3,986 955.8 4
Census Tract 9603.01 3,304 13.4 247

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About this page

This page shows demographics for a US county from the 2020 census and the American Community Survey: population, land area, density, urban share, and how the county compares to national averages for income, housing, age, and more.

Counties subdivide into census tracts, listed below with their populations. The drive-time and radius tables measure the population around the county's main population center.

Read how BlockAtlas computes population within an area →