Sully County, South Dakota

County in SD, US

By Neilsberg Research

Last updated May 1, 2026

Key Indicators

A quick look at key numbers

Population

1,526

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

Median Age

46.9

years ∙ half population younger than 46.9, half older

Diversity Index

24.6%

chance two random people differ in race and ethnicity

Nativity

4.8%

foreign-born population

95.2%Native

4.8% Foreign-born

Geographic Context

Location, size, and surroundings

About

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

Location

County in SD, US

Co-ordinates

DEC44.722325° N, 100.131399° W

DMS44° 43′ 20.37″ N, 100° 07′ 53.04″ W

Population Density & area

1.52/sq mi (0.585/km²)

Total Area

1,070 sq mi (2,771 km²)

Land Area

1,007 sq mi (2,607 km²) · 94.1%

Water Area

63 sq mi (164 km²) · 5.9%

Demographics & Living

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

Population Composition

Key characteristics of the population

Sex Distribution

55.2% male

Male 55.2%

Female 44.8%

males per 100 females

Sully County 123.1

South Dakota 103.1

United States 98

Nativity

4.8%

foreign-born population

95.2%Native

4.8% Foreign-born

% Foreign-born

Sully County 4.8%

South Dakota 4%

United States 14.1%

Age Distribution

How the population is spread across age groups

Median Age

46.9

years ∙ half population younger than 46.9, half older

Sully County

46.9

South Dakota

United States

38.9

Dependency ratio

82.3

dependents per 100 working-age adults

Sully County 82.3

South Dakota 73

United States 64.4

AGE DISTRIBUTION

Distribution of age group

Median age

	Sully County	South Dakota	United States
Age Group
Children (Under 18)	22%	24.2%	22%
Working age (18-64)	54.9%	57.8%	60.8%
Senior (65+)	23.1%	18%	17.2%
Dependency ratio
Total dependency ratio	82.3	73	64.4
Child dependency ratio	40.1	41.9	36.1
Old-age dependency ratio	42.2	31.1	28.3

Racial & Ethnic Composition

Racial and ethnic makeup and how it compares

Race & Ethnicity

White

86.5%

Black

4.5%

Asian

Hispanic

Other

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

24.6%

chance two random people differ in race and ethnicity

Sully County 24.6%

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 Sully County population

	Sully County	South Dakota	United States
Hispanic or Latino	0%	4.8%	19.3%
Mexican	0%	2.6%	11.3%
Puerto Rican	0%	0.4%	1.8%
Cuban	0%	0.1%	0.8%
Other Hispanic / Latino	0%	1.7%	5.5%
Not Hispanic or Latino	100%	95.2%	80.7%
One race	95.3%	90.8%	76.4%
White	86.5%	79.8%	57.4%
Black or African American	4.5%	2.1%	11.9%
American Indian and Alaska Native	3.9%	7.1%	0.5%
Asian	0%	1.4%	5.9%
Native Hawaiian and Other Pacific Islander	0%	0%	0.2%
Some Other Race	0.4%	0.3%	0.6%
Two or more races (Multiracial)	4.7%	4.4%	4.3%

Household & Families Composition

Household size, type, and family structure

Household structure

56.7% family

Family 56.7%

Non family 43.3%

% family households

Sully County 56.7%

South Dakota 61.3%

United States 64.2%

Average household size

2.39

persons per household

Sully County

2.39

South Dakota

2.39

United States

2.53

Household & Family COMPOSITION

Households

Percentage of Sully County population

	Sully County	South Dakota	United States
Total households	637	365,544	129,227,496
Average houshold size	2.39	2.39	2.53
Family households	361	224,058	82,990,528
Average family size	3.07	3.05	3.14
Married couple family	331	176,597	60,637,388
Other families	30	47,461	22,353,140
Male householder	13	17,711	6,572,819
Female householder	17	29,750	15,780,321
Non-family households	276	141,486	46,236,968
One-person households	218	116,755	37,140,836
Male householder	134	57,880	16,871,444
Senior (65+) living alone	62	17,403	5,225,110
Female householder	84	58,875	20,269,392
Senior (65+) living alone	58	29,381	10,089,070
Other living arrangements	58	24,731	9,096,132

Housing Profile

Housing stock, ownership, rentals, and cost burdens

Total housing units

934

housing units

Sully County 934

South Dakota 408,584

United States 143,775,355

Occupancy status

68.2% occupied

Occupied 68.2%

Vacant 31.8%

vacancy rate

Sully County 31.8%

South Dakota 10.5%

United States 10.1%

Housing Characteristics

How the housing supply is structured and used

Types of Housing unit

76%

Single family houses

76%

Apartments in multi-unit structures

7.5%

Mobile homes

16%

Boat, RV, van, etc

0.5%

Median Year Built

1977

Half of houses were built before 1977, and half after.

Historic ∙ 1939 or earlier

17.1%

Postwar & mid-century ∙ 1940 - 1969

20.2%

Late 20th century ∙ 1970 - 1999

35.3%

Modern ∙ 2000 or later

27.3%

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

Housing Characteristics

Units, rooms & bedrooms

Physical characteristics of housing units

	Sully County	South Dakota	United States
Rooms per unit
Median rooms	5.7	5.9	5.5
1–3 rooms	5.8%	13.6%	15.1%
4–6 rooms	55.7%	44.6%	51.6%
7+ rooms	38.5%	41.8%	33.4%
Bedrooms
No bedroom / studio	0%	1.9%	2.9%
1 bedroom	5.9%	10.1%	10.9%
2 bedrooms	15.8%	26.4%	25%
3 bedrooms	51.6%	32%	38.7%
4+ bedrooms	26.6%	29.6%	22.4%
At a glance
Median year built	1977	1982	1981
Total housing units	934	408,584	143,775,355

Occupancy Profile

Who is inside and how they use it

Homeownership

72.8% owners

Renter-occupied 27.2%

Owner-occupied 72.8%

homeownership rate

Sully County 72.8%

South Dakota 68.6%

United States 65.2%

Average household size

2.39

Owner-occupied

2.39

Renter-occupied

owner-occupied average size

Sully County 2.39

South Dakota 2.54

United States 2.64

Housing Characteristics

Occupied unit characteristics

Tenure, crowding, and utilities

	Sully County	South Dakota	United States
Total occupied units	637	365,544	129,227,496
Year moved in
2020 or later	20.2%	25.4%	24.8%
2010 to 2019	24.6%	39.7%	39.6%
2000 to 2009	21.7%	16.2%	16.4%
1999 or earlier	33.5%	18.7%	19.1%
Occupants per room
1.00 or fewer	100%	97.7%	96.6%
1.01 to 1.50	0%	1.6%	2.2%
1.51 or more	0%	0.7%	1.2%
Vehicles availability
No vehicles	2.4%	5.2%	8.4%
1 vehicle	24.3%	28.4%	33.1%
2 vehicles	38.5%	36.3%	36.6%
3 or more vehicles	34.9%	30.1%	21.9%
House heating fuel used
Gas	52.2%	63.1%	51.4%
Electricity	43.6%	32.4%	41.3%
Solar	0%	0%	0.3%
Fuel oil, kerosene etc	3.3%	1.3%	3.9%
All other fuels	0.6%	2.4%	2%
No fuel used	0.3%	0.8%	1.2%
Selected characteristics
Lacking complete plumbing	1.1%	0.5%	0.4%
Lacking complete kitchen	1.3%	0.9%	0.8%
No telephone service available	0.3%	1.1%	0.9%

Housing Value

What owner-occupied units are worth

Median home value

$205,400

owner-occupied units

Median value(USD)

Sully County

$205,400

South Dakota

$257,400

United States

$332,700

Housing Cost Burden

18.6%

of homeowners with a mortgage are cost-burdened

% Cost-Burdened Households

Owners with a mortgage

18.6%

Owners without a mortgage

9.5%

Renters

33%

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

	Sully County	South Dakota	United States
Property value
Median Value	$205,400	$257,400	$332,700
Under $100,000	19.8%	16.1%	11.4%
$100,000 - $200,000	29.3%	19.5%	15.8%
$200,000 - $300,000	14.4%	24.4%	17.8%
$300,000 - $500,000	24.8%	26%	26.9%
$500,000 - $1,000,000	11.6%	12.1%	20.9%
$1,000,000 and more	0%	1.8%	7.1%
Owner-occupied households
With a mortgage	36%	54.5%	60.6%
Without a mortgage	64%	45.5%	39.4%
Median monthly owner costs
With a mortgage	$1,542	$1,680	$1,963
Without a mortgage	$558	$617	$638
Gross rent
Median rent	$842	$946	$1,413

Education Profile

How educated is the community and how education pays off

Adults with a college degree

24.1%

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

Sully County 24.1%

South Dakota 31.9%

United States 35.7%

Adults without a high school diploma

3.9%

of adults (25+) without a high school diploma

Sully County 3.9%

South Dakota 6.8%

United States 10.4%

School Enrollment

Who is enrolled in school and at what level

School enrollment

298

population (age 3+) enrolled in school

Nursery / Preschool

K–12

84.9%

College / Undergraduate

3.7%

Graduate / Professional

6.4%

College-going rate (18-24 yr olds)

7.9%

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

Sully County

7.9%

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

	Sully County	South Dakota	United States
Total enrolled (age 3+)	298	216,085	80,089,790
Nursery / preschool	5%	6.1%	5.7%
K–12	84.9%	73%	67.6%
Kindergarten	1%	5.6%	5%
Elementary: Grades 1–4	24.5%	22.3%	19.8%
Elementary: Grades 5–8	27.2%	22.8%	21%
High School: Grades 9–12	32.2%	22.3%	21.7%
College or graduate school	10.1%	20.9%	26.7%
College, undergraduate	3.7%	17.1%	21%
Graduate, professional school	6.4%	3.8%	5.8%
College-going rate · 18-24 yr olds	7.9%	35.1%	40.9%
School type
Public school	80.5%	86.9%	82%
Private school	19.5%	13.1%	18%

Education Attainment by Level & Gender

What is the highest level of education completed among adults

Education attainment

1,089

population 25 years and over

Total adults (25+)

Less than 9th grade

9th-12th, no diploma

3.9%

HS graduate

38.2%

Some college no degree

18%

Associates degree

15.9%

Bachelors degree

18.5%

Graduate or professional degree

5.5%

Attainment by gender

Male vs Female

Adults (25+) · Share within each education level

* The Census Bureau did not publish education attainment by gender data for Sully County due to an insufficient sample size to produce reliable estimates.

% male · % female

Less than 9th grade

—% · —%

9th-12th, no diploma

61.9% · 38.1%

HS graduate

56.3% · 43.8%

Some college no degree

64.3% · 35.7%

Associates degree

60.7% · 39.3%

Bachelors degree

47% · 53%

Graduate or professional degree

31.7% · 68.3%

Educational Attainment Overview

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

Highest credential completed · adults 25+

	Sully County	South Dakota	United States
Population (25+)	1,089	603,746	230,807,303
Less than 9th grade	0%	2.6%	4.7%
9th–12th, no diploma	3.9%	4.2%	5.7%
High school diploma or GED	38.2%	29%	26%
Some college, no degree	18%	19.9%	19.1%
Associate's degree	15.9%	12.3%	8.8%
Bachelor's degree or higher	24.1%	31.9%	35.7%
Bachelor's degree	18.5%	21.9%	21.6%
Graduate or professional	5.5%	10%	14.1%
High School or higher	96.1%	93.2%	89.6%

Earnings by education level

percentage as applicable

Median Earnings

$48,446

Median earnings for adults 25+, by level

Less than HS graduate

$—

HS graduate

$47,786

Some college or associates

$54,375

Bachelors degree

$44,837

Graduate or professional degree

$50,714

Poverty Rate

1.5%

for ages 25+, with bachelors degree or higher

Less than HS graduate

31%

HS graduate

12.7%

Some college or associates

5.4%

Bachelors degree or higher

1.5%

Outcomes by Education Level

Earnings and poverty rates across education levels (25+)

Adults 25+

	Sully County	South Dakota	United States
Median earnings
Population 25+, with earnings	$48,446	$49,402	$52,696
Less than high school graduate	$—	$33,790	$32,485
High school graduate (includes equivalency)	$47,786	$40,544	$40,153
Some college or associate's degree	$54,375	$47,061	$47,260
Bachelor's degree	$44,837	$58,363	$70,044
Graduate or professional degree	$50,714	$72,377	$90,720
Poverty rates
Less than high school graduate	31%	28%	24.2%
High school graduate (includes equivalency)	12.7%	13.2%	14.4%
Some college or associate's degree	5.4%	8.5%	9.8%
Bachelor's degree or higher	1.5%	4.2%	4.5%

Insights for Sully 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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