57631 ZIP Code — Glenham, SD

Walworth County, South Dakota

ZIP code 57631 is located in Glenham, South Dakota, within Walworth County. It covers approximately 130.04 square miles and serves a population of 348 residents. This is a standard ZIP code in the Central (CT) timezone, served by area code 605.

About ZIP code 57631

The housing stock consists of a higher-than-average concentration of mobile homes. Most homes were built in the 1990s, giving the area an established character. Median home value is $225,000. Owner-occupancy is high at 93%, well above the national average.

The gap between median ($49,300) and mean household income suggests income inequality — a small number of higher earners pull the average up. The poverty rate of 4% is below the national average. 42% of households receive Social Security income, suggesting a notable retiree or disability population.

The dominant occupation class is management, business, and professional, with agriculture and mining as the leading industry. The average commute of 16 minutes is near the national average.

Educational attainment is near the national average, with 33% of residents holding a bachelor's degree or higher.

Overall, ZIP code 57631 reflects a community defined by high homeownership and a significant Social Security-dependent population.

348

population

130.04

sq mi land

Standard

ZIP type

Central (CT)

timezone

57631 ZIP code map

Cities in ZIP code 57631

Below are the cities the US Postal Service accepts for ZIP code 57631. Using any city not on this list may result in mail delivery delays.

City	Status
Glenham	Preferred

Nearby ZIP codes

57646 Mound City (10 mi) 57472 Selby (13.2 mi) 57658 Wakpala (15.1 mi) 57648 Pollock (17.8 mi) 57601 Mobridge (18 mi)

Demographics updated 05/2026

Population
Total population	348
Population density	3 / sq mi
State FIPS	46
County FIPS	129

Geography
Land area	130.04 sq mi
Water area	19.62 sq mi
Latitude	45.5812
Longitude	-100.2651
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	45.0%	48.9%	41.7%
$50k – $100k	35.0%	30.4%	33.8%
$100k – $200k	16.5%	16.3%	20.1%
Over $200k	3.5%	4.4%	4.4%

Demographics & statistics

348

Population

People per sq mi

58.5

Median age

$49,300

Median household income

$44,816

Per capita income

$225,000

Median home value

Median monthly rent

93.3%

Home ownership

3.7%

Poverty rate

14.4%

Unemployment

285

Housing units

32.5%

Bachelor's or higher

Age distribution

Male Female

Under 5

5–9

10–14

15–19

20–24

25–34

35–44

45–54

55–59

60–64

65–74

75–84

85+

← Male

Female →

Age summary

Group	Count	%
Under 18	21	6.0%
18 and over	327	94.0%
65 and over	134	38.5%
Median age	58.5 years

Race & ethnicity

White 97.7%

Two or more races 2.3%

Group	Count	%
White	340	97.7%
Two or more races	8	2.3%

Household income

Income range	This ZIP	County avg	State avg
Under $50k	45.0%	48.9%	41.7%
$50k – $100k	35.0%	30.4%	33.8%
$100k – $200k	16.5%	16.3%	20.1%
Over $200k	3.5%	4.4%	4.4%

Under $10k 3.1%

$10k–$15k 3.1%

$15k–$25k 1.5%

$25k–$35k 8.2%

$35k–$50k 41.2%

$50k–$75k 10.8%

$75k–$100k 11.9%

$100k–$150k 12.9%

$150k–$200k 4.6%

$200k+ 2.6%

Range	% of households
Under $10k	3.1%
$10k–$15k	3.1%
$15k–$25k	1.5%
$25k–$35k	8.2%
$35k–$50k	41.2%
$50k–$75k	10.8%
$75k–$100k	11.9%
$100k–$150k	12.9%
$150k–$200k	4.6%
$200k+	2.6%
Median income	$49,300

Housing

Home values

Under $50k 14.9%

$50k–$100k 18.8%

$100k–$150k 6.1%

$150k–$200k 7.7%

$200k–$300k 8.8%

$300k–$500k 38.1%

$500k–$1M 5.5%

Housing overview

Metric	Value
Median home value	$225,000
Median rent / month	$0
Owner occupied	93.3%
Renter occupied	6.7%
Vacant	34.9%
Single-family detached	66.8%
Large apartment buildings	0.0%
Mobile homes	33.2%
Median rooms	6.1
Avg household size (owned)	1.85

Year built

Era	%
2020 or later	2.7%
2010–2019	10.7%
2000–2009	8.7%
1990–1999	26.8%
1980–1989	4.4%
1970–1979	17.4%
1960–1969	2.0%
1950–1959	0.0%
1940–1949	6.7%
1939 or earlier	20.5%

Bedrooms

Size	% of units
No bedroom (studio)	0.0%
1 bedroom	6.7%
2 bedrooms	14.1%
3 bedrooms	44.0%
4 bedrooms	28.2%
5+ bedrooms	7.0%

Vehicles per household

Vehicles	% of households
No vehicle	0.0%
1 vehicle	12.4%
2 vehicles	63.4%
3 or more	24.2%

Heating fuel

Fuel type	%
Utility gas	20.6%
Electricity	26.3%
Propane / LP gas	47.9%
Fuel oil	3.6%
No fuel used	1.5%

Households & families

Household type	Count	%
Married-couple family	135	69.6%
Cohabiting couple	0	0.0%
Male householder, no spouse	33	17.0%
Female householder, no spouse	26	13.4%
Households with children under 18	11	5.7%
Households with seniors (65+)	82	42.3%
Average household size	1.79

Marital status

Status	Male	Female
Never married	8.2%	4.9%
Married	79.4%	81.0%
Separated	0.0%	0.0%
Widowed	4.1%	10.4%
Divorced	8.2%	3.7%

Education

Less than 9th grade 0.0%

Some HS, no diploma 6.9%

HS graduate 42.3%

Some college, no degree 13.4%

Associate's degree 4.9%

Bachelor's degree 19.5%

Graduate / professional 13.0%

Metric	%
HS diploma or higher	93.1%
Bachelor's or higher	32.5%

School enrollment (ages 3–17)

Type	Count	%
Nursery / preschool	0	0.0%
Kindergarten	0	0.0%
Elementary school	9	18.4%
High school	6	12.2%
College / grad school	34	69.4%

Employment

Industry of employment

Agriculture & mining 44.4%

Education & healthcare 20.8%

Construction 10.1%

Public administration 9.0%

Finance & real estate 4.5%

Arts, food & hospitality 4.5%

Manufacturing 2.8%

Transportation & utilities 2.8%

Wholesale trade 0.6%

Retail trade 0.6%

Occupation

Category	%
Management, business & arts	38.2%
Service	16.3%
Sales & office	1.1%
Natural resources & construction	38.2%
Production & transportation	6.2%

Employment type

Type	%
Private sector	53.4%
Government	25.8%
Self-employed	20.8%
Unpaid family workers	0.0%

Commute

Method	%
Drive alone	71.3%
Carpool	4.6%
Public transit	0.0%
Walk	2.9%
Work from home	14.9%
Other means	6.3%
Avg commute (minutes)	16.2

Poverty

All people 3.7%

Under 18 years 0.0%

18 and over 4.0%

Married-couple families 2.2%

Female-led households 0.0%

Income support

Source	% of households
Social Security	41.8%
Retirement income	25.8%
Supplemental Security	0.0%
Cash public assistance	0.0%
Food stamps / SNAP	0.0%

Health indicators

Condition	%
Obesity	32.7%
High blood pressure	34.9%
High cholesterol	34.5%
Diabetes	10.2%
Heart disease	7.7%
Stroke	3.3%
Asthma	8.3%
Arthritis	26.7%
Kidney disease	3.1%
Pulmonary disease	6.4%
Cancer	8.3%

Behavior / access	%
Smoking	16.6%
Binge drinking	18.5%
No physical activity	23.2%
Less than 7 hrs sleep	28.0%
Depression	14.1%
Fair or poor health	11.4%
Poor mental health	9.5%
Poor physical health	9.1%
No health insurance	11.0%
Visited doctor (checkup)	76.2%
Visited dentist	69.9%
Cholesterol screening	91.0%
Teeth loss	12.8%

Veterans & disability

Veterans	Count	%
Civilian veterans	26	8.0%

Disability	%
Any disability	10.3%
Under 18	0.0%
18–64 years	1.0%
65 and over	25.4%

Health insurance coverage

Type	%
Private insurance	86.8%
Public insurance	41.1%
No insurance	0.6%
Uninsured under 19	9.5%

Language & origin

Language spoken at home (age 5+)

Language	Count	%
English only	342	98.3%
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)	348	100.0%
Born in same state	348	100.0%
Born in different state	280	80.5%
Foreign born	0	0.0%
Naturalized citizen	0	0.0%
Not a US citizen	0	0.0%

Ancestry

Ancestry	Count	%
Italian	59	17%
Arab	24	6.9%
Polish	17	4.9%

Ancestry	Count	%
French	17	4.9%
German	4	1.1%
English	3	0.9%

Technology access

Metric	% of households
Computer access	55.7%
Internet access	94.8%

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

Frequently asked questions about ZIP code 57631

What city is ZIP code 57631 in?

ZIP code 57631 is primarily assigned to Glenham, South Dakota.

What county is ZIP code 57631 in?

ZIP code 57631 falls within Walworth County, South Dakota.

Does ZIP code 57631 have an older population?

39% of residents in ZIP code 57631 are 65 or older, above the national average of ~17%.

Is ZIP code 57631 mostly owner-occupied?

93% of occupied units in ZIP code 57631 are owner-occupied, well above the national average.

Does ZIP code 57631 have a large retiree population?

42% of households in ZIP code 57631 receive Social Security income, suggesting a significant retiree or disability population.

What is the population of ZIP code 57631?

ZIP code 57631 has an estimated population of 348 residents, with a density of 3 people per square mile.

What timezone is ZIP code 57631 in?

ZIP code 57631 observes the CST timezone.