County · Illinois

Jefferson County, Illinois

Jefferson County, Illinois. Jefferson County had 36,147 residents in 2025 by the Census Bureau's estimate, down 2.6% since 2020, a steeper fall than Illinois's (−0.8%). It holds 27 places (10 cities, villages and boroughs, 16 towns and townships and 1 census-designated) and 11 census tracts. GEOID 17081.

Jefferson County is the county of the Mount Vernon, IL micropolitan statistical area (the Census Bureau's July 2023 delineation).

Residents, July 2025 estimate

36,147

Census Bureau estimate (no margin published)
2020 Census count: 37,113 · ACS 2020-2024: 36,550

Median household income

$63,118

±$2,847 (90% margin)
Illinois: $83,390

Median home value

$126,000

±$6,496 (90% margin)
Illinois: $263,300

Median gross rent

$885

±$31 (90% margin)
Illinois: $1,274

How many people live in Jefferson County, and is it growing?

The 2020 Census counted 37,113 residents in Jefferson County. The Census Bureau estimates 36,147 for July 1, 2025, down 2.6% since 2020, a steeper fall than Illinois's (−0.8%). The 2020-2024 American Community Survey puts the population at 36,550 over 571 square miles of land.

July 2020→2021 −94 (36,904)
2021→2022 −446 (36,458)
2022→2023 −152 (36,306)
2023→2024 −194 (36,112)
2024→2025 +35 (36,147)

Jefferson County in Illinois. Boundaries: Census Bureau 2024.

Counts, ACS 2020-2024 5-year estimates, with the change from 2015-2019
Measure	Jefferson County	Illinois	Change since 2015-2019
Total population	36,550	12,694,798	−1,435
Households	14,820±266	5,036,449	no clear change
Average household size	2.37±0.04	2.46	no clear change
Housing units	16,629±74	5,457,452	−369

Jefferson County's population since 2000

From 40,045 in 2000 to 36,147 in 2025: down 9.7%. The 2000, 2010 and 2020 figures are census counts. The 2005 figure is the Census Bureau's intercensal estimate, revised to fit the 2000 and 2010 counts and drawn on 2010 boundaries; 2015 and 2025 are July 1 estimates made from the census before them.

2000 Census 40,045
2005 (estimate) 39,624
2010 Census 38,827
2015 (estimate) 38,290
2020 Census 37,113
2025 (estimate) 36,147

Source: The 2000, 2010 and 2020 Census counts and the Census Bureau's population estimates (intercensal 2000-2010, Vintage 2020, Vintage 2025) · Census population estimates

Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026); PEP Vintage 2025 (CO-EST2025); 2020 Census · Check it at data.census.gov

What cities and towns are in Jefferson County?

Jefferson County holds 27 places: 10 cities, villages and boroughs (incorporated places), 16 towns and townships (county subdivisions with their own government) and 1 census-designated place. The largest is Mount Vernon with 14,187 residents (2025 estimate). Places that cross a county line are listed with the share of their 2020 residents who live in this county.

Places in Jefferson County, ACS 2020-2024 5-year estimates. Ring: estimate with a coefficient of variation over 40%.

Mount Vernon	city	14,600	14,090±361	$55,357	$99,800	17.3%	100%
Mount Vernon Township	township	12,576	12,335±26	$56,971	$102,500	15.6%	100%
Shiloh Township, Jefferson County	township	6,524	6,520±26	$70,031	$148,900	14.2%	100%
Dodds Township	township	2,690	2,700±29	$62,025	$111,100	7.7%	100%
Spring Garden Township	township	2,586	2,574±22	$65,750	$104,800	16.4%	100%
Webber Township	township	2,104	1,636±223	$59,241	$119,300	13.4%	100%
Rome Township	township	1,710	1,576±210	$61,964	$144,200	8.1%	100%
Ina	village	1,641	1,560±166	$54,000	$104,200	19.7%	100%
Field Township	township	1,482	1,730±265	$70,284	$159,400	10.6%	100%
McClellan Township	township	1,269	1,047±154	$76,500	$119,400	10.3%	100%
Casner Township	township	1,209	907±197	$65,313	$136,000	10.7%	100%
Pendleton Township	township	1,191	1,454±247	$58,056	$109,500	16.2%	100%
Grand Prairie Township	township	900	988±182	$85,893	$174,300	17.0%	100%
Bald Hill Township	township	800	805±181	$98,750	$160,500	4.1%	100%
Elk Prairie Township	township	701	569±108	$51,914	$89,200	15.8%	100%
Bluford	village	630	483±101	$51,583	$94,500	13.9%	100%
Woodlawn	village	617	632±112	$72,500	$132,700	10.2%	100%
Farrington Township	township	599	783±132	$81,250	$117,000	5.2%	100%
Dix	village	469	568±154	$46,339	$100,000	10.7%	100%
Waltonville	village	408	294±65	$63,750	$111,400	15.0%	100%
Blissville TownshipGEOID 1708106496	township	400	546±214	$69,844	$176,700	27.1%	100%
Bonnie	village	374	461±118	$60,536	$73,200	12.1%	100%
Moores Prairie TownshipGEOID 1708150348	township	372	380±106	$59,107	$113,100	13.9%	100%
Belle Rive	village	309	382±98	$53,281	$94,600	8.4%	100%
OpdykeGEOID 1756198	CDP	236	246±75	$63,750	$67,800	2.5%	100%
NasonGEOID 1751726	city	199	203±79	$50,052	$73,600	29.7%	100%
Centralia	city	12,182	11,856±176	$47,807	$89,600	24.3%	0%

Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026); 2020 place-by-county parts · Check it at data.census.gov

Who lives in Jefferson County?

The median resident of Jefferson County is 41.2 years old; 22.3% are under 18 and 20.0% are 65 or older. The largest group is non-Hispanic white residents at 83.6%, then non-Hispanic residents of two or more races at 6.0%. 1.9% of residents were born outside the United States.

Age, origin and education, ACS 2020-2024 5-year estimates. Race groups are non-Hispanic; Hispanic includes any race.
Measure	Jefferson County	Illinois	Change since 2015-2019
Median age	41.2±0.4	39.0	no clear change
Under 18 years	22.3%	21.8%	–
65 years and over	20.0%±0.1 pts	17.0%	–
Hispanic or Latino (any race)	2.8%	18.8%	+0.1 pts
White alone, not Hispanic	83.6%±0.6 pts	58.1%	−1.9 pts
Black or African American alone, not Hispanic	5.8%±0.7 pts	13.3%	−2.5 pts
Asian alone, not Hispanic	1.0%±0.2 pts	5.9%	no clear change
American Indian and Alaska Native alone, not Hispanic	0.3%±0.3 pts	0.1%	–
Native Hawaiian and Other Pacific Islander alone, not Hispanic	0.0%±0.1 pts	0.0%	–
Two or more races, not Hispanic	6.0%±1.0 pts	3.4%	–
Some other race alone, not Hispanic	0.4%±0.2 pts	0.4%	–
Born outside the United States	1.9%±0.4 pts	14.7%	no clear change
Speak a language other than English at home (age 5+)	3.6%±0.6 pts	24.0%	–
Civilian veterans (age 18+)	7.7%±0.7 pts	4.8%	–
With a disability	18.3%±1.3 pts	12.1%	–
No health insurance coverage	7.2%±1.0 pts	6.9%	+1.3 pts
High school graduate or higher (age 25+)	92.3%±0.8 pts	90.5%	–
Bachelor's degree or higher (age 25+)	18.2%±1.3 pts	37.8%	no clear change
Graduate or professional degree (age 25+)	6.7%±0.7 pts	15.3%	–
Moved from another state in the past year	1.3%±0.6 pts	1.6%	–

Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026) (Data Profiles DP02, DP05) · Check it at data.census.gov

What do households in Jefferson County earn?

Half of Jefferson County's 14,820 households earn less than $63,118 a year (±$2,847), against $83,390 in Illinois. In 2015-2019 it was $61,407 in 2024 dollars; the margins of error cannot tell the two periods apart. 13.5% of residents live below the poverty line.

Income and poverty in 2024 dollars, ACS 2020-2024 5-year estimates
Measure	Jefferson County	Illinois	Change since 2015-2019
Median household income	$63,118±$2,847	$83,390	no clear change
Mean household income	$80,324±$3,270	$115,638	–
Per capita income	$33,038±$1,285	$46,406	no clear change
People below the poverty line	13.5%±1.7 pts	11.8%	−3.5 pts
Children under 18 below the poverty line	18.8%±3.5 pts	15.1%	−11.2 pts
Households receiving SNAP	17.1%±1.9 pts	13.8%	–
Households with a broadband subscription	85.7%±1.7 pts	90.8%	–

Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026) (Data Profile DP03) · Check it at data.census.gov

What does housing cost in Jefferson County?

Owners occupy 71.7% of Jefferson County's occupied homes and renters 28.3%. The median owner-occupied home is valued at $126,000 by its owner (±$6,496). The median renter pays $885 a month including utilities, and 32.1% of renters pay 35% or more of their income on rent.

Housing, ACS 2020-2024 5-year estimates
Measure	Jefferson County	Illinois	Change since 2015-2019
Median home value (owner-occupied)	$126,000±$6,496	$263,300	no clear change
Median gross rent	$885±$31	$1,274	no clear change
Renters paying 35% or more of income on rent	32.1%±5.4 pts	39.0%	no clear change
Median monthly owner costs, with a mortgage	$1,278±$45	$1,987	–
Owner-occupied homes	71.7%±1.7 pts	67.1%	no clear change
Housing units	16,629±74	5,457,452	−369
Homeowner vacancy rate	1.5%±0.9 pts	1.0%	–
Rental vacancy rate	6.0%±2.8 pts	5.0%	–
Single-family detached homes	69.0%±1.7 pts	58.2%	–
Mobile homes	17.0%±1.4 pts	2.3%	–
Built 2020 or later	0.8%±0.4 pts	0.7%	–
Built 1939 or earlier	11.1%±1.5 pts	20.2%	–

Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026) (Data Profile DP04) · Check it at data.census.gov

How many new homes is Jefferson County building?

Builders took permits for 12 new housing units across Jefferson County in 2025 (12 single-family), 0.3 per 1,000 residents.

2019 34 units
2020 6 units
2021 11 units
2022 5 units
2023 4 units
2024 6 units
2025 12 units

Source: Building Permits Survey, annual county files 2019-2025, U.S. Census Bureau · Census Building Permits Survey

How do people in Jefferson County get to work?

82.3% of Jefferson County's workers drive alone and 5.4% work from home. The average trip to work takes 19.6 minutes. The unemployment rate in 2020-2024 averaged 5.8%.

Work and commuting, ACS 2020-2024 5-year estimates
Measure	Jefferson County	Illinois	Change since 2015-2019
In the labor force (age 16+)	59.0%±1.5 pts	65.0%	–
Unemployment rate	5.8%±1.0 pts	5.8%	no clear change
Drove alone to work	82.3%±1.9 pts	65.9%	–
Carpooled	9.9%±1.5 pts	7.8%	–
Public transportation	0.3%±0.2 pts	5.8%	–
Walked	0.7%±0.3 pts	2.8%	–
Worked from home	5.4%±0.9 pts	15.9%	+1.4 pts
Mean travel time to work	19.6 min±0.7	27.8 min	no clear change

Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026) (Data Profile DP03) · Check it at data.census.gov

What are Jefferson County's census tracts?

Jefferson County is divided into 11 census tracts. Among those with a reliable estimate, median household income runs from $35,294 (Tract 510) to $74,434 (Tract 508).

Census tracts of Jefferson County, ACS 2020-2024 5-year estimates; sort by any column

Tract 50117081050100	Dix (9%)	4,142	4,088±247	$70,380	$157,300	$623	9.6%
Tract 50217081050200	Bluford (28%)	3,077	3,161±261	$59,028	$122,200	$933	14.9%
Tract 50317081050300	Waltonville (10%)	4,243	4,171±294	$74,194	$144,100	$838	11.7%
Tract 50417081050400	Belle Rive (12%)	4,733	5,004±282	$61,223	$103,600	$742	11.5%
Tract 50517081050500	Mount Vernon (34%)	3,724	3,414±339	$55,841	$167,000	$922	20.8%
Tract 50617081050600	Mount Vernon (72%)	3,084	2,957±285	$70,066	$133,700	$1,029	12.1%
Tract 50717081050700	Mount Vernon (45%)	3,669	3,431±365	$66,536	$128,400	$966	9.7%
Tract 50817081050800	Mount Vernon (29%)	4,155	4,444±341	$74,434	$158,500	$888	9.8%
Tract 50917081050900	Mount Vernon (96%)	2,351	2,454±387	$43,850	$49,600	$796	18.1%
Tract 51017081051000	Mount Vernon	1,356	1,183±248	$35,294	$52,900	$864	42.7%
Tract 51117081051100	Mount Vernon (58%)	2,579	2,243±361	$61,583	$92,200	$1,000	11.2%

Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026) · Check it at data.census.gov

How does Jefferson County compare with Illinois's other counties?

Jefferson County's rank among Illinois's counties with a reliable estimate (1 = highest)
Measure	Rank
Population	38th of 102
Growth 2020-2025	61st of 102
Residents per square mile	38th of 102
Median household income	67th of 102
Median home value	63rd of 102
Median gross rent	31st of 102
Poverty rate	41st of 102
Bachelor's degree or higher	81st of 102
Median age	67th of 102

Every county in Illinois

Source: PlainCities ranks from the American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026) and PEP Vintage 2025 · How ranks are computed

How these figures are made: methodology and release checks · reading a margin of error · every state · corrections

Not on this page: crime, weather and schools for Jefferson County are other agencies' records. Crime: the FBI's Crime Data Explorer · climate: NOAA's U.S. Climate Normals · schools: the National Center for Education Statistics' school search.