Clay County, South Dakota

County in SD, US

By Neilsberg Research

Last updated May 1, 2026

Key Indicators

A quick look at key numbers

Population

15,219

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

Median Age

24.9

years ∙ half population younger than 24.9, half older

Diversity Index

28.5%

chance two random people differ in race and ethnicity

Nativity

3.8%

foreign-born population

96.2%Native

3.8% Foreign-born

Geographic Context

Location, size, and surroundings

About

Clay County is a county in South Dakota, United States.

Location

County in SD, US

Co-ordinates

DEC42.916150° N, 96.980468° W

DMS42° 54′ 58.14″ N, 96° 58′ 49.68″ W

Population Density & area

36.94/sq mi (14.26/km²)

Total Area

417.4 sq mi (1,081.1 km²)

Land Area

412 sq mi (1,067.1 km²) · 98.7%

Water Area

5.4 sq mi (14 km²) · 1.3%

Demographics & Living

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

Population Composition

Key characteristics of the population

Sex Distribution

49.9% male

Male 49.9%

Female 50.1%

males per 100 females

Clay County 99.6

South Dakota 103.1

United States 98

Nativity

3.8%

foreign-born population

96.2%Native

3.8% Foreign-born

% Foreign-born

Clay County 3.8%

South Dakota 4%

United States 14.1%

Age Distribution

How the population is spread across age groups

Median Age

24.9

years ∙ half population younger than 24.9, half older

Clay County

24.9

South Dakota

United States

38.9

Dependency ratio

dependents per 100 working-age adults

Clay County 42

South Dakota 73

United States 64.4

AGE DISTRIBUTION

Distribution of age group

Median age

	Clay County	South Dakota	United States
Age Group
Children (Under 18)	17.4%	24.2%	22%
Working age (18-64)	70.4%	57.8%	60.8%
Senior (65+)	12.2%	18%	17.2%
Dependency ratio
Total dependency ratio	42	73	64.4
Child dependency ratio	24.7	41.9	36.1
Old-age dependency ratio	17.3	31.1	28.3

Racial & Ethnic Composition

Racial and ethnic makeup and how it compares

Race & Ethnicity

White

84.2%

Black

1.8%

Asian

Hispanic

3.3%

Other

7.7%

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

28.5%

chance two random people differ in race and ethnicity

Clay County 28.5%

South Dakota 35.3%

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 Clay County population

	Clay County	South Dakota	United States
Hispanic or Latino	3.3%	4.8%	19.3%
Mexican	2.3%	2.6%	11.3%
Puerto Rican	0.1%	0.4%	1.8%
Cuban	0%	0.1%	0.8%
Other Hispanic / Latino	1%	1.7%	5.5%
Not Hispanic or Latino	96.7%	95.2%	80.7%
One race	91.6%	90.8%	76.4%
White	84.2%	79.8%	57.4%
Black or African American	1.8%	2.1%	11.9%
American Indian and Alaska Native	2.6%	7.1%	0.5%
Asian	3%	1.4%	5.9%
Native Hawaiian and Other Pacific Islander	0%	0%	0.2%
Some Other Race	0%	0.3%	0.6%
Two or more races (Multiracial)	5.1%	4.4%	4.3%

Household & Families Composition

Household size, type, and family structure

Household structure

46.9% family

Family 46.9%

Non family 53.1%

% family households

Clay County 46.9%

South Dakota 61.3%

United States 64.2%

Average household size

2.29

persons per household

Clay County

2.29

South Dakota

2.39

United States

2.53

Household & Family COMPOSITION

Households

Percentage of Clay County population

	Clay County	South Dakota	United States
Total households	5,547	365,544	129,227,496
Average houshold size	2.29	2.39	2.53
Family households	2,599	224,058	82,990,528
Average family size	3.09	3.05	3.14
Married couple family	2,137	176,597	60,637,388
Other families	462	47,461	22,353,140
Male householder	196	17,711	6,572,819
Female householder	266	29,750	15,780,321
Non-family households	2,948	141,486	46,236,968
One-person households	2,123	116,755	37,140,836
Male householder	1,271	57,880	16,871,444
Senior (65+) living alone	246	17,403	5,225,110
Female householder	852	58,875	20,269,392
Senior (65+) living alone	268	29,381	10,089,070
Other living arrangements	825	24,731	9,096,132

Housing Profile

Housing stock, ownership, rentals, and cost burdens

Total housing units

6,262

housing units

Clay County 6,262

South Dakota 408,584

United States 143,775,355

Occupancy status

88.6% occupied

Occupied 88.6%

Vacant 11.4%

vacancy rate

Clay County 11.4%

South Dakota 10.5%

United States 10.1%

Housing Characteristics

How the housing supply is structured and used

Types of Housing unit

55.4%

Single family houses

55.4%

Apartments in multi-unit structures

39%

Mobile homes

5.5%

Boat, RV, van, etc

Median Year Built

1978

Half of houses were built before 1978, and half after.

Historic ∙ 1939 or earlier

18.7%

Postwar & mid-century ∙ 1940 - 1969

20.7%

Late 20th century ∙ 1970 - 1999

32.4%

Modern ∙ 2000 or later

28.2%

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

Housing Characteristics

Units, rooms & bedrooms

Physical characteristics of housing units

	Clay County	South Dakota	United States
Rooms per unit
Median rooms	5.1	5.9	5.5
1–3 rooms	18.8%	13.6%	15.1%
4–6 rooms	47.8%	44.6%	51.6%
7+ rooms	33.4%	41.8%	33.4%
Bedrooms
No bedroom / studio	3.2%	1.9%	2.9%
1 bedroom	11.1%	10.1%	10.9%
2 bedrooms	37.3%	26.4%	25%
3 bedrooms	22.4%	32%	38.7%
4+ bedrooms	26%	29.6%	22.4%
At a glance
Median year built	1978	1982	1981
Total housing units	6,262	408,584	143,775,355

Occupancy Profile

Who is inside and how they use it

Homeownership

50.8% owners

Renter-occupied 49.2%

Owner-occupied 50.8%

homeownership rate

Clay County 50.8%

South Dakota 68.6%

United States 65.2%

Average household size

2.72

Owner-occupied

1.85

Renter-occupied

owner-occupied average size

Clay County 2.72

South Dakota 2.54

United States 2.64

Housing Characteristics

Occupied unit characteristics

Tenure, crowding, and utilities

	Clay County	South Dakota	United States
Total occupied units	5,547	365,544	129,227,496
Year moved in
2020 or later	38.9%	25.4%	24.8%
2010 to 2019	34.5%	39.7%	39.6%
2000 to 2009	11.6%	16.2%	16.4%
1999 or earlier	15%	18.7%	19.1%
Occupants per room
1.00 or fewer	96.6%	97.7%	96.6%
1.01 to 1.50	1.9%	1.6%	2.2%
1.51 or more	1.5%	0.7%	1.2%
Vehicles availability
No vehicles	5.7%	5.2%	8.4%
1 vehicle	38%	28.4%	33.1%
2 vehicles	32.2%	36.3%	36.6%
3 or more vehicles	24.1%	30.1%	21.9%
House heating fuel used
Gas	62.9%	63.1%	51.4%
Electricity	34.4%	32.4%	41.3%
Solar	0.2%	0%	0.3%
Fuel oil, kerosene etc	0.7%	1.3%	3.9%
All other fuels	1.2%	2.4%	2%
No fuel used	0.5%	0.8%	1.2%
Selected characteristics
Lacking complete plumbing	0.8%	0.5%	0.4%
Lacking complete kitchen	0.6%	0.9%	0.8%
No telephone service available	0.5%	1.1%	0.9%

Housing Value

What owner-occupied units are worth

Median home value

$232,300

owner-occupied units

Median value(USD)

Clay County

$232,300

South Dakota

$257,400

United States

$332,700

Housing Cost Burden

25.8%

of homeowners with a mortgage are cost-burdened

% Cost-Burdened Households

Owners with a mortgage

25.8%

Owners without a mortgage

13%

Renters

49.2%

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

	Clay County	South Dakota	United States
Property value
Median Value	$232,300	$257,400	$332,700
Under $100,000	17.3%	16.1%	11.4%
$100,000 - $200,000	24.5%	19.5%	15.8%
$200,000 - $300,000	23.8%	24.4%	17.8%
$300,000 - $500,000	25.9%	26%	26.9%
$500,000 - $1,000,000	7.7%	12.1%	20.9%
$1,000,000 and more	0.9%	1.8%	7.1%
Owner-occupied households
With a mortgage	60%	54.5%	60.6%
Without a mortgage	40%	45.5%	39.4%
Median monthly owner costs
With a mortgage	$1,653	$1,680	$1,963
Without a mortgage	$676	$617	$638
Gross rent
Median rent	$770	$946	$1,413

Education Profile

How educated is the community and how education pays off

Adults with a college degree

45.4%

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

Clay County 45.4%

South Dakota 31.9%

United States 35.7%

Adults without a high school diploma

7.7%

of adults (25+) without a high school diploma

Clay County 7.7%

South Dakota 6.8%

United States 10.4%

School Enrollment

Who is enrolled in school and at what level

School enrollment

6,891

population (age 3+) enrolled in school

Nursery / Preschool

3.6%

K–12

30.1%

College / Undergraduate

54.7%

Graduate / Professional

11.6%

College-going rate (18-24 yr olds)

78.6%

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

Clay County

78.6%

South Dakota

35.1%

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

	Clay County	South Dakota	United States
Total enrolled (age 3+)	6,891	216,085	80,089,790
Nursery / preschool	3.6%	6.1%	5.7%
K–12	30.1%	73%	67.6%
Kindergarten	1.6%	5.6%	5%
Elementary: Grades 1–4	6.8%	22.3%	19.8%
Elementary: Grades 5–8	11.5%	22.8%	21%
High School: Grades 9–12	10.2%	22.3%	21.7%
College or graduate school	66.3%	20.9%	26.7%
College, undergraduate	54.7%	17.1%	21%
Graduate, professional school	11.6%	3.8%	5.8%
College-going rate · 18-24 yr olds	78.6%	35.1%	40.9%
School type
Public school	96.3%	86.9%	82%
Private school	3.7%	13.1%	18%

Education Attainment by Level & Gender

What is the highest level of education completed among adults

Education attainment

7,594

population 25 years and over

Total adults (25+)

Less than 9th grade

2.5%

9th-12th, no diploma

5.2%

HS graduate

27.2%

Some college no degree

11.7%

Associates degree

Bachelors degree

25.2%

Graduate or professional degree

20.2%

Attainment by gender

Male vs Female

Adults (25+) · Share within each education level

% male · % female

Less than 9th grade

65.3% · 34.7%

9th-12th, no diploma

35.6% · 64.4%

HS graduate

58.1% · 41.9%

Some college no degree

48.6% · 51.4%

Associates degree

33.6% · 66.4%

Bachelors degree

51.1% · 48.9%

Graduate or professional degree

57.8% · 42.2%

Educational Attainment Overview

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

Highest credential completed · adults 25+

	Clay County	South Dakota	United States
Population (25+)	7,594	603,746	230,807,303
Less than 9th grade	2.5%	2.6%	4.7%
9th–12th, no diploma	5.2%	4.2%	5.7%
High school diploma or GED	27.2%	29%	26%
Some college, no degree	11.7%	19.9%	19.1%
Associate's degree	8%	12.3%	8.8%
Bachelor's degree or higher	45.4%	31.9%	35.7%
Bachelor's degree	25.2%	21.9%	21.6%
Graduate or professional	20.2%	10%	14.1%
High School or higher	92.3%	93.2%	89.6%

Earnings by education level

percentage as applicable

Median Earnings

$46,842

Median earnings for adults 25+, by level

Less than HS graduate

$37,099

HS graduate

$39,299

Some college or associates

$41,156

Bachelors degree

$46,442

Graduate or professional degree

$59,492

Poverty Rate

13%

for ages 25+, with bachelors degree or higher

Less than HS graduate

25.4%

HS graduate

9.6%

Some college or associates

6.7%

Bachelors degree or higher

13%

Outcomes by Education Level

Earnings and poverty rates across education levels (25+)

Adults 25+

	Clay County	South Dakota	United States
Median earnings
Population 25+, with earnings	$46,842	$49,402	$52,696
Less than high school graduate	$37,099	$33,790	$32,485
High school graduate (includes equivalency)	$39,299	$40,544	$40,153
Some college or associate's degree	$41,156	$47,061	$47,260
Bachelor's degree	$46,442	$58,363	$70,044
Graduate or professional degree	$59,492	$72,377	$90,720
Poverty rates
Less than high school graduate	25.4%	28%	24.2%
High school graduate (includes equivalency)	9.6%	13.2%	14.4%
Some college or associate's degree	6.7%	8.5%	9.8%
Bachelor's degree or higher	13%	4.2%	4.5%

Insights for Clay 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.

Cite this page

Citation style

Url to be used as reference

This article is for informational purposes only and is not intended to be legal or tax advice. We recommend that you consult with a qualified professional such as a lawyer or accountant before making a decision. Many of the products and services featured here are from our affiliate partners. We may receive commissions on purchases made from our chosen links. Read advertiser disclosure.