Each edition grades its towns against each other only.
A town of 739, platted in 1881.
33% of residents are under 18 in Castlewood, above both the South Dakota town median (22%) and the median of U.S. towns (22%). Among 36 South Dakota towns, just one has a higher mean commuting time than Castlewood. Castlewood’s trail density is 1.6 miles per square mile, where South Dakota’s towns sit at 0.6 and U.S. towns at 0.4. M.O. Hanson Building is on the National Register of Historic Places. Castlewood has fewer than 1,000 residents, too few for fair grades; the figures below are still real.
In a town this size, neighbors are the best guide. Ask them anything.
Census counts: 430 in 1900, 698 in 2020. The archive holds 4 old photos and papers going back to 1907 and 2 maps from 1969 on.
1 place on the National Register of Historic Places.
Who provides power, water and the rest in Castlewood, and how to reach them.
EPA SDWIS (Oct 9, 2026) · HIFLD + EIA-861 2025 · Census 2020 ZCTAs · NCES 2024–25 · registration: vote.gov, updated Aug 3, 2026.
Ordered by what stands out in Castlewood.
The income of the median household in Castlewood is $87,000. Only 8% of working residents stay in Castlewood for work; the rest commute out. Jobs in Castlewood grew by 30 from 2013 to 2023, reaching 140. Among residents in the town, 4.4% live below the poverty line.
| Castlewood | South Dakota towns | U.S. towns | |
|---|---|---|---|
| Working residents who work in town | 7.7% | 29% | 8% |
| Below the poverty line | 4.4% | 9.5% | 9.6% |
| Median household income | $87,000 | $72,000 | $80,000 |
Census LEHD 2023 · ACS
Two of its 3 schools are below, each with the reason it’s listed. Public schools: the Castlewood School District 28-1.
| School | Level | Students | Letter |
|---|---|---|---|
| Castlewood Elementary - 02Largest public elementary schoolGrades PK–5 | Grades PK–5 | 140 | B |
| Castlewood High School - 01Largest public high schoolGrades 9–12 | Grades 9–12 | 112 | B+ |
NCES · EDFacts
In the year to September 2026, typical home values slipped 3.1%. For households in Castlewood, the share who live in a home they own is 83%. The going rate for rent for Castlewood comes to $1,139 a month.
| Castlewood | South Dakota towns | U.S. towns | |
|---|---|---|---|
| Households that own their home | 83% | 68% | 73% |
| Median rent | $1,139 a month | $962 a month | $1,185 a month |
Census ACS, 2020–24 · Zillow Home Value Index · Redfin Data Center
In Castlewood, 25% of adults 25 and older hold a bachelor’s degree or more. This South Dakota town is growing: up 5.6% since 2020, to 739 residents (2025 estimate). For Castlewood, the age of the median resident is 36.5 years.
| Castlewood | South Dakota towns | U.S. towns | |
|---|---|---|---|
| Aged 65 or older | 11% | 19% | 18% |
| Median age | 36.5 years | 39.5 years | 40.5 years |
| Bachelor’s degree or more, 25+ | 25% | 33% | 29% |
47% women, 53% men
That’s an even split within the survey’s margin of ±4.5 points. Across South Dakota, 49.2% of residents are women.
| Castlewood | SD | U.S. | |
|---|---|---|---|
| Under 10 | 19% | 13.1% | 11.6% |
| 10 to 17 | 13.9% | 11.2% | 10.3% |
| 18 to 24 | 4.2% | 9.3% | 9.1% |
| 25 to 34 | 11.1% | 12.6% | 13.7% |
| 35 to 44 | 13.9% | 12.6% | 13.2% |
| 45 to 54 | 14.7% | 10.7% | 12.2% |
| 55 to 64 | 11.8% | 12.6% | 12.7% |
| 65 to 74 | 6.2% | 11% | 10.2% |
| 75 and older | 5.1% | 7% | 7% |
| No diploma | 1.6% | 6.8% | 10.4% |
| High school | 37.6% | 29% | 26% |
| Some college | 15.6% | 19.9% | 19.1% |
| Associate’s | 20.2% | 12.3% | 8.8% |
| Bachelor’s | 20% | 21.9% | 21.6% |
| Graduate | 5% | 10% | 14.1% |
Census population estimates, 2025 · U.S. Census Bureau · ACS 2020-2024 5-year estimates · in a town of 700, single groups can be off by several points
Among 36 South Dakota towns, just 2 have a lower peak summer temperature than Castlewood. July afternoons reach 82°, January nights drop to 3° and about 34 inches of snow falls in a winter.
NOAA U.S. Climate Normals, 1991–2020
20% of adults have been diagnosed with depression in Castlewood. This South Dakota town tracks South Dakota closely on all 26 CDC measures. Two figures for adults here: 75% had a checkup this year, 32% sleep under 7 hours.
| Castlewood | South Dakota towns | U.S. towns | |
|---|---|---|---|
| Binge drink (CDC PLACES) | 19% | 19% | 16% |
| Yearly checkup (CDC PLACES) | 75% | 76% | 79% |
| Sleep under 7 hours (CDC PLACES) | 32% | 30% | 36% |
| Depression (CDC PLACES) | 20% | 22% | 23% |
CDC PLACES 2025 · modeled estimates for adults · CMS · HRSA
Expected storm and flood damage is higher than in 58% of U.S. communities. 5 flood insurance claims have been paid in Castlewood since 1978. Federal aid has come to Castlewood households in 3 declared disasters; the latest was in 2022.
FEMA flood insurance claims · FEMA disaster declarations and aid · FEMA National Risk Index · OpenFEMA
Trails & parks © OpenStreetMap contributors · Conserved land: USGS PAD-US
1 within 15 miles of the center of Castlewood
About 4 of every 100 Castlewood residents are enrolled in college, about the same as South Dakota.
Where Castlewood’s working residents go each day. Line width shows the share.
Census LEHD 2023
City in South Dakota, United States
Castlewood is a city in Hamlin County, South Dakota, United States. It is part of the Watertown, South Dakota Micropolitan Statistical Area. The population was 698 at the 2020 census, and was estimated to be 707 in 2022.
From Wikipedia, licensed CC BY-SA 4.0 · facts via Wikidata (CC0)
Short answers, built from the data on this page.
Castlewood has fewer than 1,000 residents, too few for fair grades; the figures below are still real.