Town · South Dakota
Oacoma, South Dakota
Oacoma, town, in Lyman County, South Dakota. Oacoma had 391 residents on July 1, 2025 by the Census Bureau's estimate, up 1.3% since 2020; the 2020 Census counted 386 and the ACS 2020-2024 5-year estimates put it at 548 (±112). GEOID 4646180.
Residents, July 2025 estimate
391
Census Bureau estimate (no margin published)
2020 Census count: 386 · ACS 2020-2024: 548 ±112
Median household income
$73,333
±$25,500 (90% margin)
South Dakota: $75,081
Median home value
$171,700
±$81,663 (90% margin)
South Dakota: $257,400
Median gross rent
$883
±$105 (90% margin)
South Dakota: $946
Where is Oacoma and what county is it in?
Oacoma is a town in Lyman County, South Dakota. It covers 2.6 square miles of land, 147 residents per square mile in 2020.
Source: 2024 Gazetteer and 2020 place-by-county files, U.S. Census Bureau · Census reference files
How many people live in Oacoma, and is it growing?
The Census Bureau estimates that 391 people lived in Oacoma on July 1, 2025, up 1.3% since 2020, slower than South Dakota (+5.5%). The 2020 Census counted 386 residents. The 2020-2024 American Community Survey, a five-year sample, puts the population at 548 (±112).
| Measure | Oacoma | Lyman County | Change since 2015-2019 |
|---|---|---|---|
| Total population | 548 ±112 | 3,724 | +157 |
| Households | 242 ±50 | 1,188 | no clear change |
| Average household size | 2.26 ±0.30 | 3.07 | no clear change |
| Housing units | 288 ±52 | 1,553 | no clear change |
Oacoma's population since 2000
From 390 in 2000 to 391 in 2025: up 0.3%. The 2000, 2010 and 2020 figures are census counts, each for Oacoma as it was drawn that year: a place that annexed land, or a community that has since incorporated, covered a different area then. The 2005 figure is the Census Bureau's intercensal estimate, revised to fit the 2000 and 2010 counts and drawn on 2010 boundaries; 2015 and 2025 are July 1 estimates made from the census before them.
Source: The 2000, 2010 and 2020 Census counts and the Census Bureau's population estimates (intercensal 2000-2010, Vintage 2020, Vintage 2025) · Census population estimates
Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026); Census PEP Vintage 2025 (SUB-EST2025, CO-EST2025); 2020 Census P.L. 94-171 · Check it at data.census.gov
Who lives in Oacoma?
The median resident of Oacoma is 40.2 years old; 25.4% are under 18 and 26.6% are 65 or older. The largest group is non-Hispanic white residents at 95.8%, then non-Hispanic American Indian and Alaska Native residents at 2.2%.
| Measure | Oacoma | Lyman County | Change since 2015-2019 |
|---|---|---|---|
| Median age | 40.2 ±6.3 | 36.1 | no clear change |
| Under 18 years | 25.4% ±7.5 pts | 28.0% | – |
| 65 years and over | 26.6% ±7.2 pts | 18.3% | – |
| Male | 59.7% ±7.9 pts | 52.3% | – |
| Hispanic or Latino (any race) | 2.0% ±2.5 pts | 1.2% | – |
| White alone, not Hispanic | 95.8% ±4.1 pts | 57.1% | no clear change |
| Black or African American alone, not Hispanic | 0.0% ±4.5 pts | 0.0% | – |
| Asian alone, not Hispanic | 0.0% ±4.5 pts | 0.0% | – |
| American Indian and Alaska Native alone, not Hispanic | 2.2% ±2.9 pts | 39.3% | – |
| Native Hawaiian and Other Pacific Islander alone, not Hispanic | 0.0% ±4.5 pts | 0.3% | – |
| Two or more races, not Hispanic | 0.0% ±4.5 pts | 2.0% | – |
| Some other race alone, not Hispanic | 0.0% ±4.5 pts | 0.0% | – |
| Born outside the United States | 1.8% ±2.2 pts | 0.6% | – |
| Speak a language other than English at home (age 5+) | 2.0% ±2.4 pts | 3.7% | – |
| Civilian veterans (age 18+) | 11.1% ±6.8 pts | 5.1% | – |
| With a disability | 11.7% ±6.2 pts | 13.0% | – |
| No health insurance coverage | 14.3% ±7.8 pts | 21.3% | no clear change |
| High school graduate or higher (age 25+) | 93.2% ±5.2 pts | 89.4% | – |
| Bachelor's degree or higher (age 25+) | 18.8% ±7.9 pts | 24.5% | no clear change |
| Graduate or professional degree (age 25+) | 6.3% ±3.8 pts | 4.9% | – |
| Lived in the same house a year earlier | 95.9% ±3.6 pts | 94.0% | – |
| Moved from another state in the past year | 0.0% ±4.6 pts | 1.4% | – |
Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026) (Data Profiles DP02, DP05) · Check it at data.census.gov
What do households in Oacoma earn?
Half of Oacoma's 242 households earn less than $73,333 a year (±$25,500), against $67,143 in Lyman County and $75,081 in South Dakota. In 2015-2019 it was $80,834 in 2024 dollars; the margins of error cannot tell the two periods apart.
| Measure | Oacoma | Lyman County | Change since 2015-2019 |
|---|---|---|---|
| Median household income | $73,333 ±$25,500 | $67,143 | no clear change |
| Mean household income | $87,555 ±$17,283 | $99,810 | – |
| Per capita income | $41,558 ±$7,916 | $37,079 | no clear change |
| People below the poverty line | 5.5% ±4.5 pts | 23.7% | – |
| Children under 18 below the poverty line | 0.0% ±16.4 pts | 30.1% | – |
| Households receiving SNAP | 9.5% ±7.5 pts | 11.4% | – |
| Households with a computer | 97.9% ±1.9 pts | 89.1% | – |
| Households with a broadband subscription | 88.8% ±7.4 pts | 82.4% | – |
Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026) (Data Profile DP03) · Check it at data.census.gov
What does housing cost in Oacoma?
Owners occupy 77.7% of Oacoma's occupied homes and renters 22.3%. The median owner-occupied home is valued at $171,700 by its owner (±$81,663). The median renter pays $883 a month including utilities.
| Measure | Oacoma | Lyman County | Change since 2015-2019 |
|---|---|---|---|
| Median home value (owner-occupied) | $171,700 ±$81,663 | $165,800 | no clear change |
| Median gross rent | $883 ±$105 | $651 | no clear change |
| Renters paying 35% or more of income on rent | 23.4% ±32.1 pts | 21.4% | – |
| Median monthly owner costs, with a mortgage | $1,448 ±$267 | $1,396 | – |
| Owner-occupied homes | 77.7% ±10.1 pts | 69.9% | no clear change |
| Renter-occupied homes | 22.3% ±10.1 pts | 30.1% | – |
| Housing units | 288 ±52 | 1,553 | no clear change |
| Homeowner vacancy rate | 1.1% ±1.6 pts | 0.2% | – |
| Rental vacancy rate | 6.9% ±11.1 pts | 10.1% | – |
| Single-family detached homes | 68.8% ±9.8 pts | 80.9% | – |
| Mobile homes | 14.6% ±7.9 pts | 10.8% | – |
| Built 2020 or later | 1.7% ±2.6 pts | 0.6% | – |
| Built 2010 to 2019 | 1.4% ±1.8 pts | 4.9% | – |
| Built 1939 or earlier | 9.0% ±5.7 pts | 13.1% | – |
| Households with no vehicle | 0.8% ±1.3 pts | 5.7% | – |
Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026) (Data Profile DP04) · Check it at data.census.gov
How many new homes is Oacoma building?
Builders took permits for 2 new housing units in Oacoma in 2025 (2 in single-family houses), 5.1 per 1,000 residents against 5.7 across South Dakota.
Counts of units in permits a local office issued; not every permitted unit is built. A year marked with months was reported for part of the year.
Source: Building Permits Survey, annual place files 2019-2025, U.S. Census Bureau · Census Building Permits Survey
How do people in Oacoma work and get to work?
74.3% of Oacoma's workers drive alone. The average trip to work takes 15.0 minutes.
| Measure | Oacoma | Lyman County | Change since 2015-2019 |
|---|---|---|---|
| In the labor force (age 16+) | 63.7% ±9.3 pts | 57.3% | – |
| Unemployment rate | 6.6% ±5.4 pts | 4.0% | – |
| Drove alone to work | 74.3% ±11.9 pts | 73.4% | – |
| Carpooled | 14.7% ±10.5 pts | 8.2% | – |
| Public transportation | 0.0% ±9.7 pts | 0.8% | – |
| Walked | 1.6% ±2.6 pts | 3.1% | – |
| Worked from home | 6.1% ±7.2 pts | 11.2% | – |
| Mean travel time to work | 15.0 min ±2.8 | 15.8 min | no clear change |
Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026) (Data Profile DP03) · Check it at data.census.gov
What census tracts are in Oacoma?
No census tract lies mostly in Oacoma; 1 tract reaches into it (2020 census blocks).
| Tract | Residents, 2020-2024 | Median household income |
|---|---|---|
| Tract 9726Lyman County | 2,207 | $77,375 |
Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026); 2020 block assignment files (tract share = share of the tract's census blocks in Oacoma) · Census block assignment files
How does Oacoma compare with other places in South Dakota?
By the Census Bureau's July 2025 estimates, Oacoma is the 14,215th-most populous of the 19,476 U.S. incorporated places that have one and the 136th-most populous of 310 in South Dakota.
Oacoma is not ranked by income or the other survey measures: those rankings include places of 1,000 or more residents (2020 Census) with a reliable estimate.
| Measure | Rank | Of |
|---|---|---|
| Population, July 2025 estimate | 136th | 310 |
Oacoma's figures with every place in South Dakota (CSV)
Every place in South Dakota, sortable · Compare Oacoma with other places
Source: PlainCities ranks computed from the American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026) and PEP Vintage 2025 · How ranks are computed
How reliable are the figures for Oacoma?
24 of the 57 figures for Oacoma on this page carry a coefficient of variation over 40% and are marked with a ring: they come from a small sample, so read them as rough.
The American Community Survey samples about one household in eight over five years, so every figure is an estimate with a 90% margin of error (shown under each value). A ring marks an estimate whose coefficient of variation is over 40%. A change is called only when the gap between the two periods is larger than their combined 90% margin (the square root of the sum of the two squared margins), the Census Bureau's test. How to read a margin of error.
Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026): margins of error as published · ACS technical documentation
How these figures are made: methodology and release checks · reading a margin of error · every state · corrections
Not on this page: crime, weather and schools for Oacoma are other agencies' records. Crime: the FBI's Crime Data Explorer · climate: NOAA's U.S. Climate Normals · schools: the National Center for Education Statistics' public schools in Oacoma.