County · Illinois

Warren County, Illinois

Warren County, Illinois. Warren County had 16,222 residents in 2025 by the Census Bureau's estimate, down 3.7% since 2020, a steeper fall than Illinois's (−0.8%). It holds 22 places (6 cities, villages and boroughs, 15 towns and townships and 1 census-designated) and 5 census tracts. GEOID 17187.

Residents, July 2025 estimate

16,222

Census Bureau estimate (no margin published)
2020 Census count: 16,835 · ACS 2020-2024: 16,447

Median household income

$67,385

±$6,850 (90% margin)
Illinois: $83,390

Median home value

$105,000

±$6,705 (90% margin)
Illinois: $263,300

Median gross rent

$788

±$90 (90% margin)
Illinois: $1,274

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

The 2020 Census counted 16,835 residents in Warren County. The Census Bureau estimates 16,222 for July 1, 2025, down 3.7% since 2020, a steeper fall than Illinois's (−0.8%). The 2020-2024 American Community Survey puts the population at 16,447 over 542 square miles of land.

July 2020→2021 −215 (16,622)
2021→2022 −344 (16,278)
2022→2023 −119 (16,159)
2023→2024 −43 (16,116)
2024→2025 +106 (16,222)

Warren County in Illinois. Boundaries: Census Bureau 2024.

Counts, ACS 2020-2024 5-year estimates, with the change from 2015-2019
Measure	Warren County	Illinois	Change since 2015-2019
Total population	16,447	12,694,798	−699
Households	6,787±222	5,036,449	no clear change
Average household size	2.27±0.07	2.46	no clear change
Housing units	7,587±25	5,457,452	−100

Warren County's population since 2000

From 18,735 in 2000 to 16,222 in 2025: down 13.4%. 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 18,735
2005 (estimate) 17,874
2010 Census 17,707
2015 (estimate) 17,448
2020 Census 16,835
2025 (estimate) 16,222

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 Warren County?

Warren County holds 22 places: 6 cities, villages and boroughs (incorporated places), 15 towns and townships (county subdivisions with their own government) and 1 census-designated place. The largest is Monmouth Township with 9,599 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 Warren County, ACS 2020-2024 5-year estimates. Ring: estimate with a coefficient of variation over 40%.

Monmouth Township	township	9,975	9,727±27	$61,897	$100,600	16.7%	100%
Monmouth	city	8,902	8,581±285	$61,138	$86,800	17.7%	100%
Roseville Township	township	1,135	991±184	$59,141	$104,200	9.3%	100%
Spring Grove Township	township	929	1,200±339	$79,250	$110,400	11.2%	100%
Tompkins Township	township	900	1,056±191	$82,083	$101,300	8.5%	100%
Roseville	village	892	823±166	$58,203	$85,700	7.8%	100%
Kirkwood	village	678	754±165	$67,917	$89,100	11.2%	100%
Greenbush TownshipGEOID 1718731277	township	517	473±120	$94,609	$307,800	7.8%	100%
Sumner Township, Warren County	township	505	504±153	$55,972	$84,300	3.6%	100%
Alexis	village	793	814±173	$66,250	$97,600	11.9%	56%
Coldbrook TownshipGEOID 1718715404	township	439	299±142	not published	$150,700	47.8%	100%
Floyd TownshipGEOID 1718726610	township	406	570±196	$91,855	$122,300	16.1%	100%
Kelly TownshipGEOID 1718739396	township	380	435±189	$125,405	$95,500	8.7%	100%
Ellison TownshipGEOID 1718723516	township	340	427±145	$76,528	not published	17.8%	100%
Hale TownshipGEOID 1718732226	township	334	249±184	$133,314	not published	0.0%	100%
Berwick TownshipGEOID 1718705560	township	291	168±79	$69,861	$105,900	0.0%	100%
Little YorkGEOID 1744082	village	283	379±141	$54,545	$81,200	4.7%	100%
Lenox TownshipGEOID 1718742847	township	264	88±56	$66,000	$88,800	0.0%	100%
Swan TownshipGEOID 1718774093	township	248	157±113	not published	not published	51.6%	100%
CameronGEOID 1710747	CDP	188	280±144	$92,167	$111,300	23.9%	100%
Point Pleasant TownshipGEOID 1718760898	township	172	103±69	$106,333	not published	0.0%	100%
Avon	village	704	694±200	$50,000	$62,200	23.1%	1%

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 Warren County?

The median resident of Warren County is 38.5 years old; 22.5% are under 18 and 20.0% are 65 or older. The largest group is non-Hispanic white residents at 81.1%, then Hispanic or Latino residents (of any race) at 11.1%. 6.5% 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	Warren County	Illinois	Change since 2015-2019
Median age	38.5±0.7	39.0	no clear change
Under 18 years	22.5%±0.3 pts	21.8%	–
65 years and over	20.0%±0.4 pts	17.0%	–
Hispanic or Latino (any race)	11.1%	18.8%	+1.5 pts
White alone, not Hispanic	81.1%±0.5 pts	58.1%	−2.1 pts
Black or African American alone, not Hispanic	2.7%±0.8 pts	13.3%	no clear change
Asian alone, not Hispanic	2.4%±0.2 pts	5.9%	no clear change
American Indian and Alaska Native alone, not Hispanic	0.1%±0.1 pts	0.1%	–
Native Hawaiian and Other Pacific Islander alone, not Hispanic	0.1%±0.2 pts	0.0%	–
Two or more races, not Hispanic	2.1%±0.9 pts	3.4%	–
Some other race alone, not Hispanic	0.3%±0.4 pts	0.4%	–
Born outside the United States	6.5%±0.8 pts	14.7%	no clear change
Speak a language other than English at home (age 5+)	12.0%±1.5 pts	24.0%	–
Civilian veterans (age 18+)	7.3%±1.4 pts	4.8%	–
With a disability	13.8%±1.7 pts	12.1%	–
No health insurance coverage	5.0%±1.5 pts	6.9%	no clear change
High school graduate or higher (age 25+)	87.1%±1.9 pts	90.5%	–
Bachelor's degree or higher (age 25+)	22.0%±2.4 pts	37.8%	no clear change
Graduate or professional degree (age 25+)	7.9%±1.6 pts	15.3%	–
Moved from another state in the past year	1.4%±0.7 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 Warren County earn?

Half of Warren County's 6,787 households earn less than $67,385 a year (±$6,850), against $83,390 in Illinois. In 2015-2019 it was $61,916 in 2024 dollars; the margins of error cannot tell the two periods apart. 14.6% of residents live below the poverty line.

Income and poverty in 2024 dollars, ACS 2020-2024 5-year estimates
Measure	Warren County	Illinois	Change since 2015-2019
Median household income	$67,385±$6,850	$83,390	no clear change
Mean household income	$86,803±$6,003	$115,638	–
Per capita income	$35,164±$2,360	$46,406	+$3,498
People below the poverty line	14.6%±2.7 pts	11.8%	no clear change
Children under 18 below the poverty line	24.8%±7.3 pts	15.1%	no clear change
Households receiving SNAP	16.0%±2.8 pts	13.8%	–
Households with a broadband subscription	84.7%±2.7 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 Warren County?

Owners occupy 75.2% of Warren County's occupied homes and renters 24.8%. The median owner-occupied home is valued at $105,000 by its owner (±$6,705). The median renter pays $788 a month including utilities, and 26.5% of renters pay 35% or more of their income on rent.

Housing, ACS 2020-2024 5-year estimates
Measure	Warren County	Illinois	Change since 2015-2019
Median home value (owner-occupied)	$105,000±$6,705	$263,300	no clear change
Median gross rent	$788±$90	$1,274	no clear change
Renters paying 35% or more of income on rent	26.5%±8.9 pts	39.0%	no clear change
Median monthly owner costs, with a mortgage	$1,059±$64	$1,987	–
Owner-occupied homes	75.2%±3.6 pts	67.1%	no clear change
Housing units	7,587±25	5,457,452	−100
Homeowner vacancy rate	0.6%±0.5 pts	1.0%	–
Rental vacancy rate	3.3%±3.4 pts	5.0%	–
Single-family detached homes	87.3%±2.5 pts	58.2%	–
Mobile homes	2.6%±1.2 pts	2.3%	–
Built 2020 or later	0.5%±0.7 pts	0.7%	–
Built 1939 or earlier	33.9%±3.4 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 Warren County building?

Builders took permits for 4 new housing units across Warren County in 2025 (4 single-family), 0.2 per 1,000 residents.

2019 8 units
2020 2 units
2021 3 units
2022 4 units
2023 49 units
2024 9 units
2025 4 units

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

How do people in Warren County get to work?

80.5% of Warren County's workers drive alone and 7.4% work from home. The average trip to work takes 18.8 minutes. The unemployment rate in 2020-2024 averaged 3.6%.

Work and commuting, ACS 2020-2024 5-year estimates
Measure	Warren County	Illinois	Change since 2015-2019
In the labor force (age 16+)	61.0%±2.5 pts	65.0%	–
Unemployment rate	3.6%±1.4 pts	5.8%	−4.1 pts
Drove alone to work	80.5%±3.0 pts	65.9%	–
Carpooled	5.6%±1.4 pts	7.8%	–
Public transportation	0.7%±0.7 pts	5.8%	–
Walked	4.6%±1.6 pts	2.8%	–
Worked from home	7.4%±1.7 pts	15.9%	+2.6 pts
Mean travel time to work	18.8 min±1.6	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 Warren County's census tracts?

Warren County is divided into 5 census tracts. Among those with a reliable estimate, median household income runs from $61,225 (Tract 8704) to $83,902 (Tract 8701).

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

Tract 870117187870100	Kirkwood (21%)	2,087	2,446±280	$83,902	$99,800	$948	4.8%
Tract 870217187870200	Roseville (11%)	2,573	2,309±231	$70,568	$139,200	$856	12.5%
Tract 870317187870300	Alexis (8%)	2,561	2,472±277	$65,000	$115,600	$737	19.7%
Tract 870417187870400	Monmouth (88%)	4,804	4,600±344	$61,225	$105,500	$597	11.7%
Tract 870517187870500	Monmouth (86%)	4,810	4,620±363	$63,345	$78,600	$853	20.9%

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

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

Warren County's rank among Illinois's counties with a reliable estimate (1 = highest)
Measure	Rank
Population	65th of 102
Growth 2020-2025	79th of 102
Residents per square mile	71st of 102
Median household income	49th of 102
Median home value	82nd of 102
Median gross rent	64th of 102
Poverty rate	29th of 102
Bachelor's degree or higher	42nd of 102
Median age	91st 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 Warren 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.