57231 ZIP Code — De Smet, SD

Kingsbury County, South Dakota

ZIP code 57231 is located in De Smet, South Dakota, within Kingsbury County. It covers approximately 249.28 square miles and serves a population of 1,733 residents. This is a standard ZIP code in the Central (CT) timezone, served by area code 605.

About ZIP code 57231

The housing stock consists of predominantly single-family detached homes. Most homes were built in the pre-1940, giving the area an established character. Median home value is $171,800. Owner-occupancy is high at 80%, well above the national average.

Median household income is $70,625. 39% of households receive Social Security income, suggesting a notable retiree or disability population.

The dominant occupation class is management, business, and professional, with education and healthcare as the leading industry. The average commute of 14 minutes is near the national average.

Educational attainment is near the national average, with 23% of residents holding a bachelor's degree or higher.

Overall, ZIP code 57231 reflects a community defined by high homeownership and a significant Social Security-dependent population.

1,733

population

249.28

sq mi land

Standard

ZIP type

Central (CT)

timezone

57231 ZIP code map

Cities in ZIP code 57231

Below are the cities the US Postal Service accepts for ZIP code 57231. Using any city not on this list may result in mail delivery delays.

City	Status
De Smet	Preferred

Nearby ZIP codes

57249 Lake Preston (9 mi) 57353 Iroquois (13.4 mi) 57051 Oldham (14.8 mi) 57221 Bryant (17 mi) 57323 Carthage (19.4 mi) 57212 Arlington (20 mi) 57278 Willow Lake (20 mi)

Demographics updated 05/2026

Population
Total population	1,733
Population density	7 / sq mi
State FIPS	46
County FIPS	077

Geography
Land area	249.28 sq mi
Water area	12.85 sq mi
Latitude	44.3695
Longitude	-97.5623
Timezone	Central (CT)
Area code	605

Total population by age

Gender

Race & ethnicity

Economics updated 05/2026

Household income

Income range	This ZIP	County avg	State avg
Under $50k	38.8%	37.0%	41.7%
$50k – $100k	41.0%	37.7%	33.8%
$100k – $200k	15.9%	21.3%	20.1%
Over $200k	4.2%	4.0%	4.4%

Demographics & statistics

1,733

Population

People per sq mi

44.9

Median age

$70,625

Median household income

$34,880

Per capita income

$171,800

Median home value

$711

Median monthly rent

80.3%

Home ownership

10.8%

Poverty rate

0.0%

Unemployment

730

Housing units

22.5%

Bachelor's or higher

Age distribution

Male Female

Under 5

5–9

10–14

15–19

20–24

25–34

105

35–44

100

45–54

55–59

60–64

129

65–74

121

75–84

85+

← Male

Female →

Age summary

Group	Count	%
Under 18	428	24.7%
18 and over	1,305	75.3%
65 and over	500	28.9%
Median age	44.9 years

Race & ethnicity

White 97.9%

Two or more races 1.8%

Hispanic or Latino 0.1%

Other race 0.1%

Group	Count	%
White	1,699	97.9%
Two or more races	32	1.8%
Hispanic or Latino	2	0.1%
Other race	2	0.1%

Household income

Income range	This ZIP	County avg	State avg
Under $50k	38.8%	37.0%	41.7%
$50k – $100k	41.0%	37.7%	33.8%
$100k – $200k	15.9%	21.3%	20.1%
Over $200k	4.2%	4.0%	4.4%

Under $10k 3.5%

$10k–$15k 2.6%

$15k–$25k 6.9%

$25k–$35k 6.6%

$35k–$50k 18.8%

$50k–$75k 15.0%

$75k–$100k 15.6%

$100k–$150k 18.7%

$150k–$200k 7.3%

$200k+ 5.1%

Range	% of households
Under $10k	3.5%
$10k–$15k	2.6%
$15k–$25k	6.9%
$25k–$35k	6.6%
$35k–$50k	18.8%
$50k–$75k	15.0%
$75k–$100k	15.6%
$100k–$150k	18.7%
$150k–$200k	7.3%
$200k+	5.1%
Median income	$70,625

Housing

Home values

Under $50k 7.6%

$50k–$100k 23.0%

$100k–$150k 15.1%

$150k–$200k 9.1%

$200k–$300k 18.7%

$300k–$500k 17.1%

$500k–$1M 7.6%

$1M+ 1.8%

Housing overview

Metric	Value
Median home value	$171,800
Median rent / month	$711
Owner occupied	80.3%
Renter occupied	19.7%
Vacant	20.7%
Single-family detached	79.9%
Large apartment buildings	0.7%
Mobile homes	11.6%
Median rooms	6.4
Avg household size (owned)	2.61

Year built

Era	%
2020 or later	0.0%
2010–2019	4.3%
2000–2009	13.2%
1990–1999	10.3%
1980–1989	3.5%
1970–1979	16.0%
1960–1969	8.3%
1950–1959	10.2%
1940–1949	5.5%
1939 or earlier	28.8%

Bedrooms

Size	% of units
No bedroom (studio)	0.7%
1 bedroom	3.5%
2 bedrooms	23.1%
3 bedrooms	43.0%
4 bedrooms	19.1%
5+ bedrooms	10.6%

Vehicles per household

Vehicles	% of households
No vehicle	0.6%
1 vehicle	25.1%
2 vehicles	32.7%
3 or more	41.7%

Heating fuel

Fuel type	%
Utility gas	48.0%
Electricity	23.0%
Propane / LP gas	18.5%
Fuel oil	0.4%
Wood	3.9%
No fuel used	2.3%

Households & families

Household type	Count	%
Married-couple family	385	56.1%
Cohabiting couple	33	4.8%
Male householder, no spouse	127	18.5%
Female householder, no spouse	141	20.6%
Households with children under 18	172	25.1%
Households with seniors (65+)	289	42.1%
Average household size	2.45

Marital status

Status	Male	Female
Never married	21.0%	17.5%
Married	59.7%	59.6%
Separated	1.7%	0.0%
Widowed	3.5%	14.3%
Divorced	14.1%	8.6%

Education

Less than 9th grade 4.2%

Some HS, no diploma 6.7%

HS graduate 43.7%

Some college, no degree 12.0%

Associate's degree 10.8%

Bachelor's degree 14.3%

Graduate / professional 8.2%

Metric	%
HS diploma or higher	89.1%
Bachelor's or higher	22.5%

School enrollment (ages 3–17)

Type	Count	%
Nursery / preschool	16	5.8%
Kindergarten	14	5.1%
Elementary school	172	62.1%
High school	64	23.1%
College / grad school	11	4.0%

Employment

Industry of employment

Education & healthcare 22.6%

Agriculture & mining 18.0%

Manufacturing 13.9%

Wholesale trade 9.8%

Retail trade 6.9%

Arts, food & hospitality 5.5%

Public administration 5.5%

Professional & management 4.5%

Finance & real estate 3.8%

Other services 3.8%

Construction 2.6%

Transportation & utilities 2.0%

Information 1.3%

Occupation

Category	%
Management, business & arts	36.7%
Service	19.7%
Sales & office	16.9%
Natural resources & construction	13.0%
Production & transportation	13.6%

Employment type

Type	%
Private sector	70.4%
Government	9.8%
Self-employed	17.7%
Unpaid family workers	2.1%

Commute

Method	%
Drive alone	79.9%
Carpool	8.2%
Public transit	0.0%
Walk	4.4%
Work from home	7.0%
Other means	0.6%
Avg commute (minutes)	13.5

Poverty

All people 10.8%

Under 18 years 12.6%

18 and over 10.1%

Married-couple families 5.7%

Female-led households 5.6%

Income support

Source	% of households
Social Security	39.4%
Retirement income	20.0%
Supplemental Security	2.3%
Cash public assistance	0.9%
Food stamps / SNAP	4.8%

Health indicators

Condition	%
Obesity	32.0%
High blood pressure	35.6%
High cholesterol	34.7%
Diabetes	10.4%
Heart disease	8.7%
Stroke	3.8%
Asthma	8.4%
Arthritis	28.4%
Kidney disease	3.5%
Pulmonary disease	6.8%
Cancer	9.6%

Behavior / access	%
Smoking	15.8%
Binge drinking	16.9%
No physical activity	25.4%
Less than 7 hrs sleep	26.1%
Depression	13.9%
Fair or poor health	12.0%
Poor mental health	9.5%
Poor physical health	9.3%
No health insurance	11.6%
Visited doctor (checkup)	77.6%
Visited dentist	69.3%
Cholesterol screening	91.2%
Teeth loss	14.1%

Veterans & disability

Veterans	Count	%
Civilian veterans	79	6.1%

Disability	%
Any disability	10.7%
Under 18	2.8%
18–64 years	5.9%
65 and over	26.6%

Health insurance coverage

Type	%
Private insurance	74.3%
Public insurance	39.9%
No insurance	3.9%
Uninsured under 19	3.7%

Language & origin

Language spoken at home (age 5+)

Language	Count	%
English only	1,572	90.7%
Spanish	0	0.0%
Other Indo-European	0	0.0%
Asian & Pacific Islander	0	0.0%
Other languages	0	0.0%

Place of birth & citizenship

Origin	Count	%
Native born (US)	1,727	99.7%
Born in same state	1,727	99.7%
Born in different state	1,423	82.1%
Foreign born	0	0.0%
Naturalized citizen	6	0.3%
Not a US citizen	0	0.0%

Ancestry

Ancestry	Count	%
Polish	382	22%
Italian	267	15.4%
French	129	7.4%
English	99	5.7%

Ancestry	Count	%
Dutch	84	4.8%
Arab	29	1.7%
German	4	0.2%

Technology access

Metric	% of households
Computer access	39.6%
Internet access	88.2%

Source: U.S. Census Bureau, American Community Survey 2025 estimates.

Frequently asked questions about ZIP code 57231

What city is ZIP code 57231 in?

ZIP code 57231 is primarily assigned to De Smet, South Dakota.

What county is ZIP code 57231 in?

ZIP code 57231 falls within Kingsbury County, South Dakota.

Does ZIP code 57231 have an older population?

29% of residents in ZIP code 57231 are 65 or older, above the national average of ~17%.

Is ZIP code 57231 mostly owner-occupied?

80% of occupied units in ZIP code 57231 are owner-occupied, well above the national average.

Does ZIP code 57231 have a large retiree population?

39% of households in ZIP code 57231 receive Social Security income, suggesting a significant retiree or disability population.

What is the typical home value in ZIP code 57231?

The median home value in ZIP code 57231 is $171,800.

What timezone is ZIP code 57231 in?

ZIP code 57231 observes the CST timezone.