O'Fallon Township High School District 203, Illinois

School District in IL, US

By Neilsberg Research

Last updated May 1, 2026

Key Indicators

A quick look at key numbers

Population

44,393

Source: U.S. Census Bureau American Community Survey (ACS) 2020-2024 5-Year Estimates

Median Age

39.2

years ∙ half population younger than 39.2, half older

Diversity Index

49.5%

chance two random people differ in race and ethnicity

Nativity

3.5%

foreign-born population

96.5%Native

3.5% Foreign-born

Geographic Context

Location, size, and surroundings

About

O'Fallon Township High School District 203 is a school district in Illinois, United States.

Location

School District in IL, US

Co-ordinates

DEC38.604570° N, 89.906406° W

DMS38° 36′ 16.45″ N, 89° 54′ 23.06″ W

Population Density & area

911.6/sq mi (351.8/km²)

Total Area

49.4 sq mi (127.9 km²)

Land Area

48.7 sq mi (126.2 km²) · 98.7%

Water Area

0.7 sq mi (1.7 km²) · 1.3%

Demographics & Living

Who lives here, how households are formed, and community composition

Population Composition

Key characteristics of the population

Sex Distribution

49.4% male

Male 49.4%

Female 50.6%

males per 100 females

O'Fallon Township High SD 203 97.7

Illinois 97.7

United States 98

Nativity

3.5%

foreign-born population

96.5%Native

3.5% Foreign-born

% Foreign-born

O'Fallon Township High SD 203 3.5%

Illinois 14.7%

United States 14.1%

Age Distribution

How the population is spread across age groups

Median Age

39.2

years ∙ half population younger than 39.2, half older

O'Fallon Township High SD 203

39.2

Illinois

United States

38.9

Dependency ratio

73.5

dependents per 100 working-age adults

O'Fallon Township High SD 203 73.5

Illinois 63.5

United States 64.4

AGE DISTRIBUTION

Distribution of age group

Median age

	O'Fallon Township High SD 203	Illinois	United States
Age Group
Children (Under 18)	25.4%	21.8%	22%
Working age (18-64)	57.7%	61.2%	60.8%
Senior (65+)	16.9%	17%	17.2%
Dependency ratio
Total dependency ratio	73.5	63.5	64.4
Child dependency ratio	44.1	35.7	36.1
Old-age dependency ratio	29.4	27.8	28.3

Racial & Ethnic Composition

Racial and ethnic makeup and how it compares

Race & Ethnicity

White

68.4%

Black

17.5%

Asian

2.3%

Hispanic

5.6%

Other

6.2%

Note: White, Black, and Asian refer to individuals belonging to a single race and not of Hispanic origin. Hispanics may be of any race.

Diversity Index

49.5%

chance two random people differ in race and ethnicity

O'Fallon Township High SD 203 49.5%

Illinois 60.5%

United States 61.4%

Note: The Diversity Index (DI), based on the Blau Index, measures the probability that two randomly selected individuals differ in race and ethnicity. Values range from 0 (no diversity) to 1 (high diversity) and are shown as percentages.

RACIAL & ETHNIC COMPOSITION

Race & Ethnicity

Percentage of O'Fallon Township High SD 203 population

	O'Fallon Township High SD 203	Illinois	United States
Hispanic or Latino	5.6%	18.8%	19.3%
Mexican	2.8%	14.4%	11.3%
Puerto Rican	1%	1.6%	1.8%
Cuban	0%	0.3%	0.8%
Other Hispanic / Latino	1.8%	2.5%	5.5%
Not Hispanic or Latino	94.4%	81.2%	80.7%
One race	88.8%	77.8%	76.4%
White	68.4%	58.1%	57.4%
Black or African American	17.5%	13.3%	11.9%
American Indian and Alaska Native	0.1%	0.1%	0.5%
Asian	2.3%	5.9%	5.9%
Native Hawaiian and Other Pacific Islander	0%	0%	0.2%
Some Other Race	0.5%	0.4%	0.6%
Two or more races (Multiracial)	5.6%	3.4%	4.3%

Household & Families Composition

Household size, type, and family structure

Household structure

71% family

Family 71%

Non family 29%

% family households

O'Fallon Township High SD 203 71%

Illinois 62.2%

United States 64.2%

Average household size

2.54

persons per household

O'Fallon Township High SD 203

2.54

Illinois

2.46

United States

2.53

Household & Family COMPOSITION

Households

Percentage of O'Fallon Township High SD 203 population

	O'Fallon Township High SD 203	Illinois	United States
Total households	17,472	5,036,449	129,227,496
Average houshold size	2.54	2.46	2.53
Family households	12,401	3,130,978	82,990,528
Average family size	3.03	3.14	3.14
Married couple family	10,003	2,282,435	60,637,388
Other families	2,398	848,543	22,353,140
Male householder	691	248,521	6,572,819
Female householder	1,707	600,022	15,780,321
Non-family households	5,071	1,905,471	46,236,968
One-person households	4,306	1,569,881	37,140,836
Male householder	1,699	712,191	16,871,444
Senior (65+) living alone	513	210,051	5,225,110
Female householder	2,607	857,690	20,269,392
Senior (65+) living alone	1,562	417,870	10,089,070
Other living arrangements	765	335,590	9,096,132

Housing Profile

Housing stock, ownership, rentals, and cost burdens

Total housing units

18,413

housing units

O'Fallon Township High SD 203 18,413

Illinois 5,457,452

United States 143,775,355

Occupancy status

94.9% occupied

Occupied 94.9%

Vacant 5.1%

vacancy rate

O'Fallon Township High SD 203 5.1%

Illinois 7.7%

United States 10.1%

Housing Characteristics

How the housing supply is structured and used

Types of Housing unit

75.2%

Single family houses

75.2%

Apartments in multi-unit structures

20.7%

Mobile homes

Boat, RV, van, etc

0.2%

Median Year Built

1998

Half of houses were built before 1998, and half after.

Historic ∙ 1939 or earlier

4.8%

Postwar & mid-century ∙ 1940 - 1969

10.7%

Late 20th century ∙ 1970 - 1999

38.6%

Modern ∙ 2000 or later

46%

Note: Median year built reflects occupied units only; distribution includes all units.

Housing Characteristics

Units, rooms & bedrooms

Physical characteristics of housing units

	O'Fallon Township High SD 203	Illinois	United States
Rooms per unit
Median rooms	6.5	5.6	5.5
1–3 rooms	9.5%	14.6%	15.1%
4–6 rooms	40.9%	50.9%	51.6%
7+ rooms	49.6%	34.6%	33.4%
Bedrooms
No bedroom / studio	2.4%	3.1%	2.9%
1 bedroom	7.1%	11.5%	10.9%
2 bedrooms	21.9%	27.7%	25%
3 bedrooms	29.7%	35.8%	38.7%
4+ bedrooms	38.8%	21.7%	22.4%
At a glance
Median year built	1998	1971	1981
Total housing units	18,413	5,457,452	143,775,355

Occupancy Profile

Who is inside and how they use it

Homeownership

71.4% owners

Renter-occupied 28.6%

Owner-occupied 71.4%

homeownership rate

O'Fallon Township High SD 203 71.4%

Illinois 67.1%

United States 65.2%

Average household size

2.73

Owner-occupied

2.06

Renter-occupied

owner-occupied average size

O'Fallon Township High SD 203 2.73

Illinois 2.62

United States 2.64

Housing Characteristics

Occupied unit characteristics

Tenure, crowding, and utilities

	O'Fallon Township High SD 203	Illinois	United States
Total occupied units	17,472	5,036,449	129,227,496
Year moved in
2020 or later	24.5%	23.3%	24.8%
2010 to 2019	43.9%	38.1%	39.6%
2000 to 2009	17.9%	17.3%	16.4%
1999 or earlier	13.7%	21.3%	19.1%
Occupants per room
1.00 or fewer	98.6%	97.5%	96.6%
1.01 to 1.50	0.9%	1.6%	2.2%
1.51 or more	0.5%	0.8%	1.2%
Vehicles availability
No vehicles	5.6%	11%	8.4%
1 vehicle	28.2%	35.7%	33.1%
2 vehicles	42.5%	35.1%	36.6%
3 or more vehicles	23.7%	18.3%	21.9%
House heating fuel used
Gas	58%	79.5%	51.4%
Electricity	40.5%	18.6%	41.3%
Solar	0.3%	0.1%	0.3%
Fuel oil, kerosene etc	0%	0.1%	3.9%
All other fuels	0.7%	0.8%	2%
No fuel used	0.5%	0.8%	1.2%
Selected characteristics
Lacking complete plumbing	0%	0.3%	0.4%
Lacking complete kitchen	1.8%	0.8%	0.8%
No telephone service available	0.1%	0.8%	0.9%

Housing Value

What owner-occupied units are worth

Median home value

$289,300

owner-occupied units

Median value(USD)

O'Fallon Township High SD 203

$289,300

Illinois

$263,300

United States

$332,700

Housing Cost Burden

20%

of homeowners with a mortgage are cost-burdened

% Cost-Burdened Households

Owners with a mortgage

20%

Owners without a mortgage

9.2%

Renters

42.9%

Note: Households spending 30% or more of their income on housing costs are considered cost-burdened.

Financial characteristics

Property value and housing costs

Tenure, crowding, and utilities

	O'Fallon Township High SD 203	Illinois	United States
Property value
Median Value	$289,300	$263,300	$332,700
Under $100,000	8.1%	13.7%	11.4%
$100,000 - $200,000	17%	21.5%	15.8%
$200,000 - $300,000	27.9%	22.3%	17.8%
$300,000 - $500,000	38%	27.7%	26.9%
$500,000 - $1,000,000	8.3%	12.1%	20.9%
$1,000,000 and more	0.7%	2.7%	7.1%
Owner-occupied households
With a mortgage	70.5%	60.8%	60.6%
Without a mortgage	29.5%	39.2%	39.4%
Median monthly owner costs
With a mortgage	$2,112	$1,987	$1,963
Without a mortgage	$800	$792	$638
Gross rent
Median rent	$1,336	$1,274	$1,413

Education Profile

How educated is the community and how education pays off

Adults with a college degree

50.9%

of adults 25+ with a bachelor's degree or higher

O'Fallon Township High SD 203 50.9%

Illinois 37.8%

United States 35.7%

Adults without a high school diploma

2.7%

of adults (25+) without a high school diploma

O'Fallon Township High SD 203 2.7%

Illinois 9.6%

United States 10.4%

School Enrollment

Who is enrolled in school and at what level

School enrollment

12,158

population (age 3+) enrolled in school

Nursery / Preschool

7.1%

K–12

70.1%

College / Undergraduate

15.8%

Graduate / Professional

7.1%

College-going rate (18-24 yr olds)

40.6%

of 18-24-year-olds in college or graduate school

O'Fallon Township High SD 203

40.6%

Illinois

41.4%

United States

40.9%

Enrollment & school type

Enrollment levels, college-going rate, and public vs private school split

Population 3+ currently enrolled in a school

	O'Fallon Township High SD 203	Illinois	United States
Total enrolled (age 3+)	12,158	3,051,569	80,089,790
Nursery / preschool	7.1%	6.3%	5.7%
K–12	70.1%	67.3%	67.6%
Kindergarten	5.4%	4.9%	5%
Elementary: Grades 1–4	21.6%	19.5%	19.8%
Elementary: Grades 5–8	21.2%	20.8%	21%
High School: Grades 9–12	21.9%	22.1%	21.7%
College or graduate school	22.8%	26.4%	26.7%
College, undergraduate	15.8%	19.8%	21%
Graduate, professional school	7.1%	6.6%	5.8%
College-going rate · 18-24 yr olds	40.6%	41.4%	40.9%
School type
Public school	77.2%	80.5%	82%
Private school	22.8%	19.5%	18%

Education Attainment by Level & Gender

What is the highest level of education completed among adults

Education attainment

30,244

population 25 years and over

Total adults (25+)

Less than 9th grade

0.9%

9th-12th, no diploma

1.8%

HS graduate

16.4%

Some college no degree

19.3%

Associates degree

10.7%

Bachelors degree

27.3%

Graduate or professional degree

23.6%

Attainment by gender

Male vs Female

Adults (25+) · Share within each education level

% male · % female

Less than 9th grade

26.5% · 73.5%

9th-12th, no diploma

43.8% · 56.2%

HS graduate

44.7% · 55.3%

Some college no degree

50.8% · 49.2%

Associates degree

47.8% · 52.2%

Bachelors degree

44.7% · 55.3%

Graduate or professional degree

50.2% · 49.8%

Educational Attainment Overview

Distribution and key education attainment rates for adults (25+)

Highest credential completed · adults 25+

	O'Fallon Township High SD 203	Illinois	United States
Population (25+)	30,244	8,767,004	230,807,303
Less than 9th grade	0.9%	4.6%	4.7%
9th–12th, no diploma	1.8%	5%	5.7%
High school diploma or GED	16.4%	25.1%	26%
Some college, no degree	19.3%	19.2%	19.1%
Associate's degree	10.7%	8.3%	8.8%
Bachelor's degree or higher	50.9%	37.8%	35.7%
Bachelor's degree	27.3%	22.6%	21.6%
Graduate or professional	23.6%	15.3%	14.1%
High School or higher	97.3%	90.5%	89.6%

Earnings by education level

percentage as applicable

Median Earnings

$62,373

Median earnings for adults 25+, by level

Less than HS graduate

$30,990

HS graduate

$40,727

Some college or associates

$55,957

Bachelors degree

$68,042

Graduate or professional degree

$93,429

Poverty Rate

2.3%

for ages 25+, with bachelors degree or higher

Less than HS graduate

16.5%

HS graduate

6.9%

Some college or associates

5.6%

Bachelors degree or higher

2.3%

Outcomes by Education Level

Earnings and poverty rates across education levels (25+)

Adults 25+

	O'Fallon Township High SD 203	Illinois	United States
Median earnings
Population 25+, with earnings	$62,373	$55,582	$52,696
Less than high school graduate	$30,990	$34,655	$32,485
High school graduate (includes equivalency)	$40,727	$40,965	$40,153
Some college or associate's degree	$55,957	$47,813	$47,260
Bachelor's degree	$68,042	$73,326	$70,044
Graduate or professional degree	$93,429	$91,623	$90,720
Poverty rates
Less than high school graduate	16.5%	21.6%	24.2%
High school graduate (includes equivalency)	6.9%	14.4%	14.4%
Some college or associate's degree	5.6%	9.9%	9.8%
Bachelor's degree or higher	2.3%	4.5%	4.5%

Insights for O'Fallon Township High School District 203, by topic

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