Duncan Flag

Duncan

County:
Mercer County
County Seat:
No
Area (mi²):
36.636
State:
Illinois

Duncan is located in Mercer County, Illinois. Duncan has a 2025 population of 256. Duncan is currently declining at a rate of 0% annually and its population has decreased by -0.78% since the most recent census, which recorded a population of 258 in 2020.

The average household income in Duncan is $82,538 with a poverty rate of 7.84%. The median age in Duncan is 48.8 years: 35.6 years for males, and 62.6 years for females.

256
Total Population
7
Density (mi²)
0 0%
Growth

Duncan Population

Duncan Population

Data after 2023 is projected based on recent change

Demographics

The racial composition of Duncan includes 100% White, and smaller percentages for and multiracial populations.

Population by Race

White (100.0%)

Race
Population
Percentage (of total)
White255100%

Duncan Marital Status

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

Married

Widowed

Divorced

Separated

Never Married

Economics and Income Statistics

Duncan's average per capita income is $40,938. Household income levels show a median of $90,357. The poverty rate stands at 7.84%.

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
Households$90,357$82,538
Families$90,000$85,030
Married Families$90,000-
Non Families-$76,309

$40,938

Average Income

$90,357

Median Household Income

7.84%

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)