St. Louis County, Missouri

County in MO, US

By Neilsberg Research

Last updated May 1, 2026

Key Indicators

A quick look at key numbers

Population

995,569

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

Median Age

40.3

years ∙ half population younger than 40.3, half older

Diversity Index

55.9%

chance two random people differ in race and ethnicity

Nativity

8.4%

foreign-born population

91.6%Native

8.4% Foreign-born

Geographic Context

Location, size, and surroundings

About

St. Louis County is a county in Missouri, United States.

Location

County in MO, US

Co-ordinates

DEC38.640688° N, 90.446073° W

DMS38° 38′ 26.48″ N, 90° 26′ 45.86″ W

Population Density & area

1,960/sq mi (756.7/km²)

Total Area

523.4 sq mi (1,355.5 km²)

Land Area

508 sq mi (1,315.7 km²) · 97.1%

Water Area

15.4 sq mi (39.8 km²) · 2.9%

Demographics & Living

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

Population Composition

Key characteristics of the population

Sex Distribution

47.8% male

Male 47.8%

Female 52.2%

males per 100 females

St. Louis County 91.7

Missouri 97.2

United States 98

Nativity

8.4%

foreign-born population

91.6%Native

8.4% Foreign-born

% Foreign-born

St. Louis County 8.4%

Missouri 4.5%

United States 14.1%

Age Distribution

How the population is spread across age groups

Median Age

40.3

years ∙ half population younger than 40.3, half older

St. Louis County

40.3

Missouri

United States

38.9

Dependency ratio

69.8

dependents per 100 working-age adults

St. Louis County 69.8

Missouri 67.3

United States 64.4

AGE DISTRIBUTION

Distribution of age group

Median age

	St. Louis County	Missouri	United States
Age Group
Children (Under 18)	22%	22.3%	22%
Working age (18-64)	58.9%	59.8%	60.8%
Senior (65+)	19.1%	17.9%	17.2%
Dependency ratio
Total dependency ratio	69.8	67.3	64.4
Child dependency ratio	37.3	37.4	36.1
Old-age dependency ratio	32.5	29.9	28.3

Racial & Ethnic Composition

Racial and ethnic makeup and how it compares

Race & Ethnicity

White

61.4%

Black

24%

Asian

4.9%

Hispanic

3.9%

Other

5.8%

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

55.9%

chance two random people differ in race and ethnicity

St. Louis County 55.9%

Missouri 40%

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 St. Louis County population

	St. Louis County	Missouri	United States
Hispanic or Latino	3.9%	5.2%	19.3%
Mexican	2.3%	3.2%	11.3%
Puerto Rican	0.2%	0.4%	1.8%
Cuban	0.1%	0.1%	0.8%
Other Hispanic / Latino	1.2%	1.4%	5.5%
Not Hispanic or Latino	96.1%	94.8%	80.7%
One race	90.8%	90%	76.4%
White	61.4%	76.3%	57.4%
Black or African American	24%	10.9%	11.9%
American Indian and Alaska Native	0.1%	0.2%	0.5%
Asian	4.9%	2.1%	5.9%
Native Hawaiian and Other Pacific Islander	0%	0.1%	0.2%
Some Other Race	0.5%	0.4%	0.6%
Two or more races (Multiracial)	5.3%	4.8%	4.3%

Household & Families Composition

Household size, type, and family structure

Household structure

61.7% family

Family 61.7%

Non family 38.3%

% family households

St. Louis County 61.7%

Missouri 62.1%

United States 64.2%

Average household size

2.36

persons per household

St. Louis County

2.36

Missouri

2.4

United States

2.53

Household & Family COMPOSITION

Households

Percentage of St. Louis County population

	St. Louis County	Missouri	United States
Total households	413,849	2,508,227	129,227,496
Average houshold size	2.36	2.4	2.53
Family households	255,411	1,558,009	82,990,528
Average family size	3.02	3.03	3.14
Married couple family	183,709	1,166,368	60,637,388
Other families	71,702	391,641	22,353,140
Male householder	18,008	115,975	6,572,819
Female householder	53,694	275,666	15,780,321
Non-family households	158,438	950,218	46,236,968
One-person households	135,312	781,034	37,140,836
Male householder	54,383	351,809	16,871,444
Senior (65+) living alone	17,170	107,203	5,225,110
Female householder	80,929	429,225	20,269,392
Senior (65+) living alone	41,040	215,073	10,089,070
Other living arrangements	23,126	169,184	9,096,132

Housing Profile

Housing stock, ownership, rentals, and cost burdens

Total housing units

446,192

housing units

St. Louis County 446,192

Missouri 2,825,287

United States 143,775,355

Occupancy status

92.8% occupied

Occupied 92.8%

Vacant 7.2%

vacancy rate

St. Louis County 7.2%

Missouri 11.2%

United States 10.1%

Housing Characteristics

How the housing supply is structured and used

Types of Housing unit

76.6%

Single family houses

76.6%

Apartments in multi-unit structures

23%

Mobile homes

0.3%

Boat, RV, van, etc

Median Year Built

1969

Half of houses were built before 1969, and half after.

Historic ∙ 1939 or earlier

9.7%

Postwar & mid-century ∙ 1940 - 1969

42.9%

Late 20th century ∙ 1970 - 1999

36.9%

Modern ∙ 2000 or later

10.5%

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

Housing Characteristics

Units, rooms & bedrooms

Physical characteristics of housing units

	St. Louis County	Missouri	United States
Rooms per unit
Median rooms	5.9	5.7	5.5
1–3 rooms	10.6%	11.5%	15.1%
4–6 rooms	50%	53.4%	51.6%
7+ rooms	39.5%	35%	33.4%
Bedrooms
No bedroom / studio	1.2%	2%	2.9%
1 bedroom	9.5%	9.7%	10.9%
2 bedrooms	28%	26.1%	25%
3 bedrooms	36.2%	41.3%	38.7%
4+ bedrooms	25.2%	20.9%	22.4%
At a glance
Median year built	1969	1979	1981
Total housing units	446,192	2,825,287	143,775,355

Occupancy Profile

Who is inside and how they use it

Homeownership

69.2% owners

Renter-occupied 30.8%

Owner-occupied 69.2%

homeownership rate

St. Louis County 69.2%

Missouri 68.1%

United States 65.2%

Average household size

2.49

Owner-occupied

2.06

Renter-occupied

owner-occupied average size

St. Louis County 2.49

Missouri 2.54

United States 2.64

Housing Characteristics

Occupied unit characteristics

Tenure, crowding, and utilities

	St. Louis County	Missouri	United States
Total occupied units	413,849	2,508,227	129,227,496
Year moved in
2020 or later	22.1%	24.7%	24.8%
2010 to 2019	38.5%	40%	39.6%
2000 to 2009	16.7%	16.5%	16.4%
1999 or earlier	22.8%	18.8%	19.1%
Occupants per room
1.00 or fewer	98.6%	98.3%	96.6%
1.01 to 1.50	1%	1.2%	2.2%
1.51 or more	0.4%	0.5%	1.2%
Vehicles availability
No vehicles	6.6%	6.6%	8.4%
1 vehicle	37%	33%	33.1%
2 vehicles	39.1%	37.5%	36.6%
3 or more vehicles	17.2%	22.8%	21.9%
House heating fuel used
Gas	76%	57.7%	51.4%
Electricity	23.4%	38.8%	41.3%
Solar	0.1%	0.1%	0.3%
Fuel oil, kerosene etc	0.1%	0.2%	3.9%
All other fuels	0.2%	2.8%	2%
No fuel used	0.3%	0.4%	1.2%
Selected characteristics
Lacking complete plumbing	0.2%	0.4%	0.4%
Lacking complete kitchen	0.6%	0.8%	0.8%
No telephone service available	0.5%	0.9%	0.9%

Housing Value

What owner-occupied units are worth

Median home value

$276,800

owner-occupied units

Median value(USD)

St. Louis County

$276,800

Missouri

$230,300

United States

$332,700

Housing Cost Burden

22.4%

of homeowners with a mortgage are cost-burdened

% Cost-Burdened Households

Owners with a mortgage

22.4%

Owners without a mortgage

12.7%

Renters

48.4%

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

	St. Louis County	Missouri	United States
Property value
Median Value	$276,800	$230,300	$332,700
Under $100,000	11.2%	15.9%	11.4%
$100,000 - $200,000	22.1%	25.7%	15.8%
$200,000 - $300,000	20.9%	24.1%	17.8%
$300,000 - $500,000	26.5%	23.6%	26.9%
$500,000 - $1,000,000	15.5%	9.1%	20.9%
$1,000,000 and more	3.8%	1.6%	7.1%
Owner-occupied households
With a mortgage	64.1%	60.2%	60.6%
Without a mortgage	35.9%	39.8%	39.4%
Median monthly owner costs
With a mortgage	$1,753	$1,524	$1,963
Without a mortgage	$698	$546	$638
Gross rent
Median rent	$1,209	$1,033	$1,413

Education Profile

How educated is the community and how education pays off

Adults with a college degree

47.4%

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

St. Louis County 47.4%

Missouri 32.4%

United States 35.7%

Adults without a high school diploma

5.5%

of adults (25+) without a high school diploma

St. Louis County 5.5%

Missouri 8.2%

United States 10.4%

School Enrollment

Who is enrolled in school and at what level

School enrollment

239,585

population (age 3+) enrolled in school

Nursery / Preschool

7.4%

K–12

68.2%

College / Undergraduate

17.4%

Graduate / Professional

College-going rate (18-24 yr olds)

40.5%

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

St. Louis County

40.5%

Missouri

38.1%

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

	St. Louis County	Missouri	United States
Total enrolled (age 3+)	239,585	1,440,482	80,089,790
Nursery / preschool	7.4%	6.3%	5.7%
K–12	68.2%	69.4%	67.6%
Kindergarten	5.2%	5.1%	5%
Elementary: Grades 1–4	19.8%	20.5%	19.8%
Elementary: Grades 5–8	21.1%	21.7%	21%
High School: Grades 9–12	22.1%	22%	21.7%
College or graduate school	24.4%	24.3%	26.7%
College, undergraduate	17.4%	18.7%	21%
Graduate, professional school	7%	5.6%	5.8%
College-going rate · 18-24 yr olds	40.5%	38.1%	40.9%
School type
Public school	72.1%	80.3%	82%
Private school	27.9%	19.7%	18%

Education Attainment by Level & Gender

What is the highest level of education completed among adults

Education attainment

693,174

population 25 years and over

Total adults (25+)

Less than 9th grade

1.8%

9th-12th, no diploma

3.7%

HS graduate

20.7%

Some college no degree

18.6%

Associates degree

7.8%

Bachelors degree

27%

Graduate or professional degree

20.4%

Attainment by gender

Male vs Female

Adults (25+) · Share within each education level

% male · % female

Less than 9th grade

47.8% · 52.2%

9th-12th, no diploma

51% · 49%

HS graduate

47.6% · 52.4%

Some college no degree

44.2% · 55.8%

Associates degree

43.9% · 56.1%

Bachelors degree

47.5% · 52.5%

Graduate or professional degree

46.4% · 53.6%

Educational Attainment Overview

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

Highest credential completed · adults 25+

	St. Louis County	Missouri	United States
Population (25+)	693,174	4,243,115	230,807,303
Less than 9th grade	1.8%	2.7%	4.7%
9th–12th, no diploma	3.7%	5.5%	5.7%
High school diploma or GED	20.7%	30.2%	26%
Some college, no degree	18.6%	20.8%	19.1%
Associate's degree	7.8%	8.4%	8.8%
Bachelor's degree or higher	47.4%	32.4%	35.7%
Bachelor's degree	27%	19.8%	21.6%
Graduate or professional	20.4%	12.6%	14.1%
High School or higher	94.5%	91.9%	89.6%

Earnings by education level

percentage as applicable

Median Earnings

$56,448

Median earnings for adults 25+, by level

Less than HS graduate

$34,366

HS graduate

$36,932

Some college or associates

$45,322

Bachelors degree

$71,634

Graduate or professional degree

$93,919

Poverty Rate

3.8%

for ages 25+, with bachelors degree or higher

Less than HS graduate

22.3%

HS graduate

13.4%

Some college or associates

9.1%

Bachelors degree or higher

3.8%

Outcomes by Education Level

Earnings and poverty rates across education levels (25+)

Adults 25+

	St. Louis County	Missouri	United States
Median earnings
Population 25+, with earnings	$56,448	$49,030	$52,696
Less than high school graduate	$34,366	$32,024	$32,485
High school graduate (includes equivalency)	$36,932	$38,607	$40,153
Some college or associate's degree	$45,322	$44,914	$47,260
Bachelor's degree	$71,634	$61,818	$70,044
Graduate or professional degree	$93,919	$75,454	$90,720
Poverty rates
Less than high school graduate	22.3%	26.4%	24.2%
High school graduate (includes equivalency)	13.4%	14.4%	14.4%
Some college or associate's degree	9.1%	9.7%	9.8%
Bachelor's degree or higher	3.8%	4.3%	4.5%

Insights for St. Louis County, by topic

Income By year By race By age By gender

Population By year By race By age By gender

About Neilsberg Research

Neilsberg Research team are data scientists with expertise in processing, analysis and visualization of big data helping small businesses make right decisions.

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