Jefferson County Demographics

A map of Jefferson County's Population by Race

Race	2024 Pop	2020 Pop	2024 %	2020 %
White	30,570	31,182	83.6%	84.0%
Multiracial	2,207	1,745	6.0%	4.7%
Black	2,137	2,783	5.8%	7.5%
Hispanic	1,030	899	2.8%	2.4%
Asian	351	352	1.0%	0.9%
Native American/Other	255	152	0.7%	0.4%

Jefferson County, Illinois has an estimated population of 36,550, a slight decrease from the 37,113 recorded in the 2020 Census. The population is 83.6% White, 6.0% Multiracial, 5.8% Black, 2.8% Hispanic, 1.0% Asian, and 0.7% Native American/Other. 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 has become slightly more racially diverse since the 2020 Census. It is considerably less diverse than Illinois 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 28.6% in 2020 and 29.3% in the most recent ACS estimates.

Jefferson County is ranked the 38th most populous county in Illinois, out of 102 counties. Jefferson County was ranked the 37th most populous county in the 2020 Census.

Jefferson County's White Population

30,570 residents of Jefferson County, or 83.6% of the population, identify as White. The share of White residents in Jefferson County is significantly higher than in Illinois overall, where 58.1% of the population is White. Jefferson County ranks 67th statewide in terms of White residents as a share of the population, out of 102 counties.

Since the 2020 Census, Jefferson County's White population has declined by an estimated 2.0%. White residents' share of Jefferson County's population has remained roughly unchanged at 83.6%.

Jefferson County is less White than neighboring Franklin County (94.1% White), Marion County (89.1% White), Hamilton County (94.7% White), Washington County (94.8% White), and Perry County (84.9% White).

Jefferson County's Black Population

2,137 residents of Jefferson County, or 5.8% of the population, identify as Black. The share of Black residents in Jefferson County is lower than in Illinois overall, where 13.3% of the population is Black. Jefferson County ranks 25th statewide in terms of Black residents as a share of the population, out of 102 counties.

Since the 2020 Census, Jefferson County's Black population has declined by an estimated 23.2%. Black residents' share of Jefferson County's population has decreased from 7.5% to 5.8%.

Jefferson County is more Black than neighboring Franklin County (0.4% Black), Marion County (2.9% Black), Hamilton County (0.2% Black), and Washington County (1.2% Black). Jefferson County is less Black than neighboring Perry County (7.6% Black).

Jefferson County's Asian Population

351 residents of Jefferson County, or 1.0% of the population, identify as Asian. The share of Asian residents in Jefferson County is slightly lower than in Illinois overall, where 5.9% of the population is Asian. Jefferson County ranks 26th statewide in terms of Asian residents as a share of the population, out of 102 counties.

Since the 2020 Census, Jefferson County's Asian population has remained roughly the same. Asian residents' share of Jefferson County's population has remained roughly unchanged at 1.0%.

Jefferson County is more Asian than neighboring Franklin County (0.4% Asian), Marion County (0.7% Asian), Hamilton County (0.5% Asian), Washington County (0.2% Asian), and Perry County (0.4% Asian).

Jefferson County's Hispanic Population

1,030 residents of Jefferson County, or 2.8% of the population, identify as Hispanic. The share of Hispanic residents in Jefferson County is significantly lower than in Illinois overall, where 18.8% of the population is Hispanic. Jefferson County ranks 61st statewide in terms of Hispanic residents as a share of the population, out of 102 counties.

Since the 2020 Census, Jefferson County's Hispanic population has grown by an estimated 14.6%. Hispanic residents' share of Jefferson County's population has remained roughly unchanged at 2.8%.

Jefferson County is more Hispanic than neighboring Franklin County (2% Hispanic), Marion County (2.2% Hispanic), Hamilton County (0.7% Hispanic), and Washington County (1.6% Hispanic). Jefferson County is less Hispanic than neighboring Perry County (3.7% Hispanic).

Jefferson County's Native American/Other Population

255 residents of Jefferson County, or 0.7% 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 Illinois overall, where 0.5% of the population is Native American/Other. Jefferson County ranks 51st statewide in terms of Native American/Other residents as a share of the population, out of 102 counties.

Since the 2020 Census, Jefferson County's Native American/Other population has grown by an estimated 67.8%. Native American/Other residents' share of Jefferson County's population has remained roughly unchanged at 0.7%.

Jefferson County is more Native American/Other than neighboring Franklin County (0.3% Native American/Other), Hamilton County (0.6% Native American/Other), Washington County (0.2% Native American/Other), and Perry County (0.2% Native American/Other). Jefferson County is less Native American/Other than neighboring Marion County (0.9% Native American/Other).

Jefferson County's Multiracial Population

2,207 residents of Jefferson County, or 6.0% of the population, identify as Multiracial. The share of Multiracial residents in Jefferson County is slightly higher than in Illinois overall, where 3.4% of the population is Multiracial. Jefferson County ranks 10th statewide in terms of Multiracial residents as a share of the population, out of 102 counties.

Since the 2020 Census, Jefferson County's Multiracial population has grown by an estimated 26.5%. Multiracial residents' share of Jefferson County's population has increased from 4.7% to 6.0%.

Jefferson County is more Multiracial than neighboring Franklin County (2.8% Multiracial), Marion County (4.2% Multiracial), Hamilton County (3.2% Multiracial), Washington County (2% Multiracial), and Perry County (3.2% 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.