Jefferson County Demographics

A map of Jefferson County's Population by Race

Race	2024 Pop	2020 Pop	2024 %	2020 %
White	28,414	26,430	85.7%	85.6%
Hispanic	3,638	3,256	11.0%	10.5%
Multiracial	855	751	2.6%	2.4%
Native American/Other	189	263	0.6%	0.9%
Asian	42	118	0.1%	0.4%
Black	16	73	0.0%	0.2%

Jefferson County, Idaho has an estimated population of 33,154, an increase from the 30,891 recorded in the 2020 Census. The population is 85.7% White, 11.0% Hispanic, 2.6% Multiracial, 0.6% Native American/Other, 0.1% Asian, and 0.0% Black. This demographic dot map shows the population of Jefferson County, with one dot drawn for each person counted by the Census, color-coded by race.

Jefferson is about as racially diverse as it was in the 2020 Census. It is considerably less diverse than Idaho overall. Demographers use a diversity index to measure the probability that two randomly selected individuals belong to different racial or ethnic groups. In Jefferson County, that probability was 25.6% in 2020 and 25.3% in the most recent ACS estimates.

Jefferson County is ranked the 12th most populous county in Idaho, out of 44 counties. Jefferson County was ranked the 12th most populous county in the 2020 Census.

Jefferson County's White Population

28,414 residents of Jefferson County, or 85.7% of the population, identify as White. The share of White residents in Jefferson County is higher than in Idaho overall, where 78.6% of the population is White. Jefferson County ranks 19th statewide in terms of White residents as a share of the population, out of 44 counties.

Since the 2020 Census, Jefferson County's White population has grown by an estimated 7.5%. White residents' share of Jefferson County's population has remained roughly unchanged at 85.7%.

Jefferson County is more White than neighboring Clark County (63.1% White), Bingham County (73.7% White), Madison County (83.5% White), and Bonneville County (80.2% White). Jefferson County is less White than neighboring Butte County (88.7% White).

Jefferson County's Black Population

16 residents of Jefferson County, or 0.0% of the population, identify as Black. The share of Black residents in Jefferson County is comparable to the share in Idaho overall, where 0.7% of the population is Black. Jefferson County ranks 18th statewide in terms of Black residents as a share of the population, out of 44 counties.

Since the 2020 Census, Jefferson County's Black population has declined by an estimated 78.1%. Black residents' share of Jefferson County's population has remained roughly unchanged at 0.0%.

Jefferson County is less Black than neighboring Bingham County (0.2% Black), Madison County (1% Black), and Bonneville County (0.3% Black).

Jefferson County's Asian Population

42 residents of Jefferson County, or 0.1% of the population, identify as Asian. The share of Asian residents in Jefferson County is comparable to the share in Idaho overall, where 1.3% of the population is Asian. Jefferson County ranks 25th statewide in terms of Asian residents as a share of the population, out of 44 counties.

Since the 2020 Census, Jefferson County's Asian population has declined by an estimated 64.4%. Asian residents' share of Jefferson County's population has remained roughly unchanged at 0.1%.

Jefferson County is more Asian than neighboring Clark County (0% Asian), and Butte County (0% Asian). Jefferson County is less Asian than neighboring Bingham County (0.3% Asian), Madison County (1.5% Asian), and Bonneville County (0.9% Asian).

Jefferson County's Hispanic Population

3,638 residents of Jefferson County, or 11.0% of the population, identify as Hispanic. The share of Hispanic residents in Jefferson County is slightly lower than in Idaho overall, where 13.6% of the population is Hispanic. Jefferson County ranks 19th statewide in terms of Hispanic residents as a share of the population, out of 44 counties.

Since the 2020 Census, Jefferson County's Hispanic population has grown by an estimated 11.7%. Hispanic residents' share of Jefferson County's population has increased from 10.5% to 11.0%.

Jefferson County is more Hispanic than neighboring Madison County (9.8% Hispanic), and Butte County (6.4% Hispanic). Jefferson County is less Hispanic than neighboring Clark County (28.7% Hispanic), Bingham County (17.8% Hispanic), and Bonneville County (14.5% Hispanic).

Jefferson County's Native American/Other Population

189 residents of Jefferson County, or 0.6% of the population, identify as American Indian/Alaska Native/Native Hawaiian/Pacific Islander/Other. The share of Native American/Other residents in Jefferson County is comparable to the share in Idaho overall, where 1.5% of the population is Native American/Other. Jefferson County ranks 32nd statewide in terms of Native American/Other residents as a share of the population, out of 44 counties.

Since the 2020 Census, Jefferson County's Native American/Other population has declined by an estimated 28.1%. Native American/Other residents' share of Jefferson County's population has remained roughly unchanged at 0.6%.

Jefferson County is more Native American/Other than neighboring Butte County (0.3% Native American/Other). Jefferson County is less Native American/Other than neighboring Clark County (7.1% Native American/Other), Bingham County (4.9% Native American/Other), Madison County (1.4% Native American/Other), and Bonneville County (0.9% Native American/Other).

Jefferson County's Multiracial Population

855 residents of Jefferson County, or 2.6% of the population, identify as Multiracial. The share of Multiracial residents in Jefferson County is comparable to the share in Idaho overall, where 4.2% of the population is Multiracial. Jefferson County ranks 35th statewide in terms of Multiracial residents as a share of the population, out of 44 counties.

Since the 2020 Census, Jefferson County's Multiracial population has grown by an estimated 13.8%. Multiracial residents' share of Jefferson County's population has remained roughly unchanged at 2.6%.

Jefferson County is more Multiracial than neighboring Clark County (1.1% Multiracial). Jefferson County is less Multiracial than neighboring Bingham County (3.2% Multiracial), Madison County (2.8% Multiracial), Bonneville County (3.3% Multiracial), and Butte County (4.5% Multiracial).

Sources: Most recent population estimates are from the 2020-2024 American Community Survey 5-Year Estimates. 2020 population counts and map data are from 2020 Census State Redistricting Data. Geographic data are from Census TIGER/Line Shapefiles.