Monmouth Flag

Monmouth

County:
Warren County
County Seat:
Yes
Area (mi²):
4.242
State:
Illinois

Monmouth is a city located in Warren County, Illinois. Monmouth has a 2025 population of 8,569 . It is also the county seat of Warren County . Monmouth is currently declining at a rate of -0.81% annually and its population has decreased by -3.89% since the most recent census, which recorded a population of 8,916 in 2020.

The average household income in Monmouth is $75,937 with a poverty rate of 16.54%. The median age in Monmouth is 35 years: 33.8 years for males, and 37.8 years for females. For every 100 females there are 94.9 males.

8.6K
Total Population
2,020
Density (mi²)
-70 -0.81%
Growth

Monmouth Population

Monmouth Population

Data after 2023 is projected based on recent change

Demographics

The racial composition of Monmouth includes 75.46% White, 8.09% other race, 4.69% Black or African American, 4.05% Asian, and smaller percentages for Native American, Native Hawaiian or Pacific Islander and multiracial populations.

Population by Race

White (75.46%)

Other race (8.09%)

Two or more races (4.74%)

Black or African American (4.69%)

Asian (4.05%)

Native American (2.24%)

Native Hawaiian or Pacific Islander (0.74%)

Race
Population
Percentage (of total)
White6,63675.46%
Other race7118.09%
Two or more races4174.74%
Black or African American4124.69%
Asian3564.05%
Native American1972.24%
Native Hawaiian or Pacific Islander650.74%

Monmouth Marital Status

OverallMalesFemales0%10%20%30%40%50%60%70%80%90%100%

Married

Widowed

Divorced

Separated

Never Married

Economics and Income Statistics

Monmouth's average per capita income is $39,820. Household income levels show a median of $59,690. The poverty rate stands at 16.54%.

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$87,276-
Families$74,821$78,877
Households$59,690$75,937
Non Families$39,095$63,573

$39,820

Average Income

$59,690

Median Household Income

16.54%

Poverty Rate

Nearby Cities

Sources

  1. US Census State Population Estimates - Most recent state estimates from the Census Bureau's Population Estimates Program
  2. US Census County Population Estimates - Most recent county estimates from the Census Bureau's Population Estimates Program
  3. American Community Survey (2009 - 2013)
  4. Census QuickFacts
  5. Historical Populations of States and Counties (1790 - 1990)