Monmouth township

County:: Warren County
County Seat:: No
Area (mi²):: 36.831
State:: Illinois

Monmouth township is located in Warren County, Illinois. Monmouth township has a 2025 population of 9,365. Monmouth township is currently declining at a rate of -1.08% annually and its population has decreased by -5.76% since the most recent census, which recorded a population of 9,937 in 2020.

The average household income in Monmouth township is $81,697 with a poverty rate of 15.17%. The median age in Monmouth township is 35.8 years: 34.5 years for males, and 38.2 years for females.

Demographics

The racial composition of Monmouth township includes 77.25% White, 7.26% other race, 4.21% Black or African American, 3.64% Asian, and smaller percentages for Native American, Native Hawaiian or Pacific Islander and multiracial populations.

Population by Race

White

Other race

Two or more races

Black or African American

Asian

Native American

Native Hawaiian or Pacific Islander

Race	Population	Percentage (of total)
White	7,560	77.25%
Other race	711	7.26%
Two or more races	486	4.97%
Black or African American	412	4.21%
Asian	356	3.64%
Native American	197	2.01%
Native Hawaiian or Pacific Islander	65	0.66%

Monmouth township Marital Status

Married

Widowed

Divorced

Separated

Never Married

Economics and Income Statistics

Monmouth township's average per capita income is $41,178. Household income levels show a median of $60,911. The poverty rate stands at 15.17%.

Families: A family includes the owner or renter of the home along with everyone related to them - whether through birth, marriage, or adoption. This includes relatives like spouses, children, parents, siblings, grandparents, and any other family members.

Households: A household includes all the people who occupy a housing unit (such as a house or apartment) as their usual place of residence.

Non Families: A nonfamily household is either someone living alone or when the owner/renter lives with people they aren't related to, like roommates.

Name	Median	Mean
Married Families	$94,533	-
Families	$77,951	$88,786
Households	$60,911	$81,697
Non Families	$40,943	$62,387

$41,178

Average Income

$60,911

Median Household Income

15.17%

Poverty Rate