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South Dakota ZIP Codes
Buffalo County
Fort Thompson, SD
57339
57339 ZIP Code — Fort Thompson, SD
Buffalo County, South Dakota
ZIP code 57339 is located in
Fort Thompson ,
South Dakota ,
within Buffalo County .
It covers approximately 54.23 square miles and serves a population of
1,341 residents.
This is a standard ZIP code in the Central (CT) timezone,
served by area code 605 .
About ZIP code 57339
The housing stock consists of a higher-than-average concentration of mobile homes. Most homes were built in the 1970s, giving the area an established character. Median home value is $109,100. Renters make up the majority at 58%, typical of denser urban areas.
Median household income is $26,429. Poverty affects 44% of residents, above the national average. SNAP benefit usage at 33% of households reflects economic stress in the area. 31% of households receive Social Security income, suggesting a notable retiree or disability population.
The dominant occupation class is service, with education and healthcare as the leading industry. The average commute of 13 minutes is near the national average.
College attainment at 5% is below the national average, consistent with a trades and production-oriented local economy.
Health indicators show elevated rates of diabetes (15%), smoking (39%) compared to national benchmarks. 47% of residents lack health insurance, above the national average.
Overall, ZIP code 57339 reflects a community defined by a trades-oriented workforce, economic challenges above the national average, a significant Social Security-dependent population, and elevated reliance on food assistance.
57339 ZIP code map
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Cities in ZIP code 57339
Below are the cities the US Postal Service accepts for ZIP code 57339. Using any city not on this list may result in mail delivery delays.
Nearby ZIP codes
Demographics
updated 05/2026
Population
Total population
1,341
Population density
25 / sq mi
State FIPS
46
County FIPS
017
Geography
Land area
54.23 sq mi
Water area
10.52 sq mi
Latitude
44.0641
Longitude
-99.3415
Timezone
Central (CT)
Area code
605
Economics
updated 05/2026
Household income
Income range
This ZIP
County avg
State avg
Under $50k
73.9%
69.6%
41.7%
$50k – $100k
23.3%
26.7%
33.8%
$100k – $200k
2.7%
3.7%
20.1%
Over $200k
0.0%
0.0%
4.4%
Demographics & statistics
$26,429
Median household income
$109,100
Median home value
Age distribution
Age summary
Group Count % Under 18 510 38.0% 18 and over 831 62.0% 65 and over 84 6.3% Median age 23.4 years
Race & ethnicity
American Indian / Alaska Native
89.4%
Group Count % American Indian / Alaska Native 1,216 89.4% White 106 7.8% Hispanic or Latino 19 1.4% Two or more races 19 1.4%
Household income
Income range
This ZIP
County avg
State avg
Under $50k
73.9%
69.6%
41.7%
$50k – $100k
23.3%
26.7%
33.8%
$100k – $200k
2.7%
3.7%
20.1%
Over $200k
0.0%
0.0%
4.4%
Range % of households Under $10k 25.3% $10k–$15k 9.1% $15k–$25k 14.3% $25k–$35k 3.4% $35k–$50k 12.2% $50k–$75k 18.0% $75k–$100k 9.8% $100k–$150k 7.0% $150k–$200k 0.9% Median income $26,429
Housing
Housing overview
Metric Value Median home value $109,100 Median rent / month $542 Owner occupied 41.8% Renter occupied 58.2% Vacant 16.5% Single-family detached 69.7% Large apartment buildings 1.3% Mobile homes 17.8% Median rooms 5.0 Avg household size (owned) 4.09
Year built
Era % 2020 or later 0.0% 2010–2019 2.3% 2000–2009 3.8% 1990–1999 12.0% 1980–1989 15.0% 1970–1979 33.3% 1960–1969 21.1% 1950–1959 4.3% 1940–1949 1.3% 1939 or earlier 6.9%
Bedrooms
Size % of units No bedroom (studio) 1.5% 1 bedroom 12.2% 2 bedrooms 16.5% 3 bedrooms 45.0% 4 bedrooms 16.0% 5+ bedrooms 8.7%
Vehicles per household
Vehicles % of households No vehicle 19.8% 1 vehicle 37.2% 2 vehicles 26.2% 3 or more 16.8%
Heating fuel
Fuel type % Utility gas 1.5% Electricity 20.7% Propane / LP gas 73.5% Wood 3.7% No fuel used 0.6%
Households & families
Household type Count % Married-couple family 64 19.5% Cohabiting couple 34 10.4% Male householder, no spouse 98 29.9% Female householder, no spouse 132 40.2% Households with children under 18 165 50.3% Households with seniors (65+) 79 24.1% Average household size 4.08
Marital status
Status Male Female Never married 61.8% 60.1% Married 23.9% 19.4% Separated 0.8% 2.8% Widowed 8.6% 5.5% Divorced 5.0% 12.2%
Education
Some HS, no diploma
19.8%
Some college, no degree
17.2%
Graduate / professional
0.2%
Metric % HS diploma or higher 78.7% Bachelor's or higher 5.4%
School enrollment (ages 3–17)
Type Count % Nursery / preschool 54 14.6% Kindergarten 21 5.7% Elementary school 152 41.0% High school 124 33.4% College / grad school 20 5.4%
Employment
Industry of employment
Education & healthcare
30.8%
Public administration
14.8%
Arts, food & hospitality
11.9%
Professional & management
8.3%
Finance & real estate
5.4%
Agriculture & mining
2.6%
Transportation & utilities
2.3%
Occupation
Category % Management, business & arts 19.4% Service 37.0% Sales & office 16.1% Natural resources & construction 15.0% Production & transportation 12.4%
Employment type
Type % Private sector 45.6% Government 48.4% Self-employed 6.0% Unpaid family workers 0.0%
Commute
Method % Drive alone 73.5% Carpool 9.1% Public transit 0.0% Walk 3.6% Work from home 10.1% Other means 3.6% Avg commute (minutes) 13.0
Poverty
Married-couple families
25.0%
Female-led households
69.8%
Income support
Source % of households Social Security 30.5% Retirement income 13.7% Supplemental Security 16.8% Cash public assistance 14.6% Food stamps / SNAP 32.9%
Health indicators
Condition % Obesity 42.7% High blood pressure 32.0% High cholesterol 25.1% Diabetes 15.1% Heart disease 7.6% Stroke 5.0% Asthma 13.9% Arthritis 22.1% Kidney disease 3.8% Pulmonary disease 9.5% Cancer 4.2%
Behavior / access % Smoking 38.9% Binge drinking 20.3% No physical activity 36.5% Less than 7 hrs sleep 35.9% Depression 19.8% Fair or poor health 25.5% Poor mental health 18.7% Poor physical health 16.1% No health insurance 19.2% Visited doctor (checkup) 75.4% Visited dentist 47.3% Cholesterol screening 79.4% Teeth loss 36.1%
Veterans & disability
Veterans Count % Civilian veterans 72 8.7%
Disability % Any disability 15.5% Under 18 0.6% 18–64 years 22.8% 65 and over 41.7%
Health insurance coverage
Type % Private insurance 10.9% Public insurance 43.7% No insurance 47.4% Uninsured under 19 27.6%
Language & origin
Language spoken at home (age 5+)
Language Count % English only 1,132 84.4% Spanish 18 1.6% 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) 1,341 100.0% Born in same state 1,336 99.6% Born in different state 1,247 93.0% Foreign born 5 0.4% Naturalized citizen 0 0.0% Not a US citizen 0 0.0%
Ancestry
Ancestry Count % Arab 83 6.2% Polish 18 1.3% English 5 0.4%
Ancestry Count % French 5 0.4% Dutch 5 0.4% Italian 3 0.2%
Technology access
Metric % of households Computer access 24.5% Internet access 71.3%
Source: U.S. Census Bureau, American Community Survey 2025 estimates.
Frequently asked questions about ZIP code 57339
What city is ZIP code 57339 in?
ZIP code 57339 is primarily assigned to Fort Thompson, South Dakota.
What county is ZIP code 57339 in?
ZIP code 57339 falls within Buffalo County, South Dakota.
What is the poverty rate in ZIP code 57339?
44% of residents in ZIP code 57339 live below the poverty line, above the national average.
Is ZIP code 57339 family-oriented?
38% of residents in ZIP code 57339 are under 18, reflecting a younger, family-oriented community.
How educated is the population of ZIP code 57339?
5% of residents hold a bachelor's degree or higher — below the national average of ~33%, consistent with a trades-oriented local economy.
Is ZIP code 57339 mostly rentals?
58% of occupied units in ZIP code 57339 are renter-occupied.
What timezone is ZIP code 57339 in?
ZIP code 57339 observes the CST timezone.
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