City · South Dakota
Castlewood, South Dakota
Castlewood, city, in Hamlin County, South Dakota. Castlewood had 739 residents on July 1, 2025 by the Census Bureau's estimate, up 5.6% since 2020; the 2020 Census counted 698 and the ACS 2020-2024 5-year estimates put it at 804 (±156). GEOID 4610500.
Residents, July 2025 estimate
739
Census Bureau estimate (no margin published)
2020 Census count: 698 · ACS 2020-2024: 804 ±156
Median household income
$87,045
±$13,266 (90% margin)
South Dakota: $75,081
Median home value
$198,200
±$26,332 (90% margin)
South Dakota: $257,400
Median gross rent
$1,139
±$98 (90% margin)
South Dakota: $946
Where is Castlewood and what county is it in?
Castlewood is a city in Hamlin County, South Dakota. It covers 1.2 square miles of land, 607 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 Castlewood, and is it growing?
The Census Bureau estimates that 739 people lived in Castlewood on July 1, 2025, up 5.6% since 2020, in line with South Dakota (+5.5%). The 2020 Census counted 698 residents. The 2020-2024 American Community Survey, a five-year sample, puts the population at 804 (±156).
| Measure | Castlewood | Hamlin County | Change since 2015-2019 |
|---|---|---|---|
| Total population | 804 ±156 | 6,373 | +185 |
| Households | 292 ±54 | 2,194 | no clear change |
| Average household size | 2.75 ±0.37 | 2.83 | no clear change |
| Housing units | 307 ±56 | 2,860 | no clear change |
Castlewood's population since 2000
From 666 in 2000 to 739 in 2025: up 11.0%. The 2000, 2010 and 2020 figures are census counts, each for Castlewood 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 Castlewood?
The median resident of Castlewood is 36.5 years old; 33.0% are under 18 and 11.3% are 65 or older. The largest group is non-Hispanic white residents at 90.8%, then non-Hispanic residents of two or more races at 6.8%.
| Measure | Castlewood | Hamlin County | Change since 2015-2019 |
|---|---|---|---|
| Median age | 36.5 ±3.6 | 31.8 | no clear change |
| Under 18 years | 33.0% ±5.9 pts | 33.1% | – |
| 65 years and over | 11.3% ±4.8 pts | 14.3% | – |
| Male | 52.7% ±4.5 pts | 51.5% | – |
| Hispanic or Latino (any race) | 0.5% ±1.0 pts | 5.9% | – |
| White alone, not Hispanic | 90.8% ±4.1 pts | 91.2% | −6.8 pts |
| Black or African American alone, not Hispanic | 0.6% ±0.8 pts | 0.1% | – |
| Asian alone, not Hispanic | 0.0% ±3.1 pts | 0.3% | – |
| American Indian and Alaska Native alone, not Hispanic | 0.0% ±3.1 pts | 0.2% | – |
| Native Hawaiian and Other Pacific Islander alone, not Hispanic | 0.0% ±3.1 pts | 0.0% | – |
| Two or more races, not Hispanic | 6.8% ±4.1 pts | 2.2% | – |
| Some other race alone, not Hispanic | 1.2% ±1.6 pts | 0.2% | – |
| Born outside the United States | 0.7% ±1.1 pts | 3.9% | – |
| Speak a language other than English at home (age 5+) | 0.6% ±1.1 pts | 5.7% | – |
| Civilian veterans (age 18+) | 8.2% ±3.5 pts | 6.0% | – |
| With a disability | 10.4% ±3.3 pts | 7.5% | – |
| No health insurance coverage | 10.0% ±6.8 pts | 7.7% | – |
| High school graduate or higher (age 25+) | 98.4% ±1.5 pts | 91.9% | – |
| Bachelor's degree or higher (age 25+) | 25.0% ±6.5 pts | 24.5% | no clear change |
| Graduate or professional degree (age 25+) | 5.0% ±3.2 pts | 6.1% | – |
| Lived in the same house a year earlier | 96.6% ±2.8 pts | 91.2% | – |
| Moved from another state in the past year | 1.4% ±1.6 pts | 1.3% | – |
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 Castlewood earn?
Half of Castlewood's 292 households earn less than $87,045 a year (±$13,266), against $87,101 in Hamlin County and $75,081 in South Dakota. In 2015-2019 it was $81,533 in 2024 dollars; the margins of error cannot tell the two periods apart.
| Measure | Castlewood | Hamlin County | Change since 2015-2019 |
|---|---|---|---|
| Median household income | $87,045 ±$13,266 | $87,101 | no clear change |
| Mean household income | $92,403 ±$15,570 | $109,883 | – |
| Per capita income | $34,158 ±$4,895 | $39,106 | no clear change |
| People below the poverty line | 4.4% ±3.3 pts | 6.9% | – |
| Children under 18 below the poverty line | 5.7% ±5.8 pts | 9.5% | – |
| Households receiving SNAP | 4.8% ±4.0 pts | 3.2% | – |
| Households with a computer | 96.2% ±7.5 pts | 96.8% | – |
| Households with a broadband subscription | 80.1% ±9.7 pts | 90.2% | – |
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 Castlewood?
Owners occupy 82.5% of Castlewood's occupied homes and renters 17.5%. The median owner-occupied home is valued at $198,200 by its owner (±$26,332). The median renter pays $1,139 a month including utilities, and 61.5% of renters pay 35% or more of their income on rent.
| Measure | Castlewood | Hamlin County | Change since 2015-2019 |
|---|---|---|---|
| Median home value (owner-occupied) | $198,200 ±$26,332 | $208,600 | no clear change |
| Median gross rent | $1,139 ±$98 | $800 | +$388 |
| Renters paying 35% or more of income on rent | 61.5% ±26.1 pts | 19.5% | – |
| Median monthly owner costs, with a mortgage | $1,319 ±$190 | $1,555 | – |
| Owner-occupied homes | 82.5% ±7.2 pts | 82.0% | no clear change |
| Renter-occupied homes | 17.5% ±7.2 pts | 18.0% | – |
| Housing units | 307 ±56 | 2,860 | no clear change |
| Homeowner vacancy rate | 0.0% ±9.8 pts | 0.0% | – |
| Rental vacancy rate | 8.9% ±14.4 pts | 5.3% | – |
| Single-family detached homes | 85.3% ±6.5 pts | 88.4% | – |
| Mobile homes | 2.6% ±2.6 pts | 4.9% | – |
| Built 2020 or later | 0.7% ±1.2 pts | 2.9% | – |
| Built 2010 to 2019 | 7.8% ±7.0 pts | 11.4% | – |
| Built 1939 or earlier | 33.9% ±8.3 pts | 31.7% | – |
| Households with no vehicle | 1.7% ±5.1 pts | 1.3% | – |
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 Castlewood building?
Builders took permits for 2 new housing units in Castlewood in 2025 (2 in single-family houses), 2.7 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 Castlewood work and get to work?
79.5% of Castlewood's workers drive alone. The average trip to work takes 25.2 minutes.
| Measure | Castlewood | Hamlin County | Change since 2015-2019 |
|---|---|---|---|
| In the labor force (age 16+) | 78.2% ±6.1 pts | 70.0% | – |
| Unemployment rate | 1.7% ±2.0 pts | 0.5% | – |
| Drove alone to work | 79.5% ±7.3 pts | 73.4% | – |
| Carpooled | 14.4% ±6.7 pts | 12.0% | – |
| Public transportation | 0.0% ±5.5 pts | 0.0% | – |
| Walked | 2.5% ±2.8 pts | 7.3% | – |
| Worked from home | 3.6% ±2.7 pts | 7.0% | – |
| Mean travel time to work | 25.2 min ±4.7 | 22.2 min | +8.9 min |
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 Castlewood?
No census tract lies mostly in Castlewood; 1 tract reaches into it (2020 census blocks).
| Tract | Residents, 2020-2024 | Median household income |
|---|---|---|
| Tract 9551Hamlin County | 2,757 | $88,750 |
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 Castlewood) · Census block assignment files
How does Castlewood compare with other places in South Dakota?
By the Census Bureau's July 2025 estimates, Castlewood is the 11,572nd-most populous of the 19,476 U.S. incorporated places that have one and the 86th-most populous of 310 in South Dakota.
Castlewood 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 | 86th | 310 |
Castlewood's figures with every place in South Dakota (CSV)
Every place in South Dakota, sortable · Compare Castlewood 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 Castlewood?
23 of the 57 figures for Castlewood 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 Castlewood 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 Castlewood.