Foster township Flag

Foster township

County:
Marion County
County Seat:
No
Area (mi²):
35.557
State:
Illinois

Foster township is located in Marion County, Illinois. Foster township has a 2025 population of 340. Foster township is currently declining at a rate of -1.16% annually and its population has decreased by -6.08% since the most recent census, which recorded a population of 362 in 2020.

The average household income in Foster township is $116,884 with a poverty rate of 3.41%.The median age in Foster township is 37.8 years: 42.3 years for males, and 37.1 years for females.

340
Total Population
10
Density (mi²)
-4 -1.16%
Growth

Foster township Population

Foster township Population

Data after 2023 is projected based on recent change

Demographics

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

Population by Race

Race
Population
Percentage (of total)
White411100%

Foster township Marital Status

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

Married

Widowed

Divorced

Separated

Never Married

Economics and Income Statistics

Foster township's average per capita income is $70,814. Household income levels show a median of $120,125. The poverty rate stands at 3.41%.

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$130,436-
Families$130,407$130,404
Households$120,125$116,884
Non Families$78,250$61,886

$70,814

Average Income

$120,125

Median Household Income

3.41%

Poverty Rate

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)