Castlewood is a city in Hamlin County, South Dakota, home to about 804 people across 1.1 square miles. Its ZIP code is 57223.
Homes sold for a median of $315 per square foot in the three months ending August 2026, a buyer’s market.
Mostly Castlewood; also Claremont Colony and Poinsett Colony
Each card is that ZIP code’s whole market, including any part outside Castlewood. Seller’s market: under 4 months of supply; buyer’s market: over 6. Methodology
We’re writing up Castlewood’s story and what everyday life there is like, for people thinking about moving in.
Are you a local agent who knows Castlewood well? Agents who advertise here will be able to write the guide. Advertise on OfferBacked
| Nearest major airport | Minneapolis–Saint Paul International Airport / Wold–Chamberlain Field (MSP)186 miles away |
|---|---|
| Closer regional airport | Watertown Regional Airport (ATY)14 miles away |
| Nearest city of 250,000+ | Minneapolis, MN184 miles away |
| Nearest city of 1 million+ | Chicago, IL510 miles away |
Straight-line distances from the center of Castlewood; driving is longer.
Source: Airports from OurAirports (scheduled passenger service); city centers and populations from the U.S. Census Bureau.
Source: Members of Congress from the congress-legislators project; districts from the Census Bureau’s relationship files; governor and mayor from Wikidata.
Castlewood had 698 residents in the 2020 census, up 5% since 2000.
It’s the 101st largest of 440 towns in South Dakota by population.
Hamlin County grew from 5,945 residents in 1900 to 6,164 in 2020.
Hamlin County, 1900–2020
Source: U.S. Census Bureau decennial censuses (counties 1900–1990 from the Bureau’s historical county file).
Average highs peak around 81°F in summer, and winter lows average 2°F. About 24.9 inches of rain and melted snow fall in a typical year.
Source: NOAA 1991–2020 climate normals, Castlewood, SD weather station (about a mile away).
1,725 jobs at 213 businesses in Hamlin County. The biggest industries by employees:
Source: U.S. Census Bureau County Business Patterns 2022 (private employers; jobs counted where people work).
Nearest hospitals
Source: Hospitals from CMS Hospital General Information (ratings are CMS overall star ratings); straight-line distances.
Public schools here are run by Castlewood School District 28-1. Check each district’s attendance zones for a specific address.
| School | Grades | Students | Type | Distance |
|---|---|---|---|---|
| Castlewood Elementary - 02Castlewood | Pre-K–5 | 140 | Public | 0.6 mi |
| Claremont Colony Elementary - 04Castlewood | K–8 | 17 | Public | 3.6 mi |
| Castlewood Middle School - 03Castlewood | 6–8 | 76 | Public | 0.6 mi |
| Castlewood High School - 01Castlewood | 9–12 | 112 | Public | 0.6 mi |
Source: U.S. Department of Education, NCES: Common Core of Data (2024-2025) for public schools. Listed by address; we don’t rate schools.
Buying or selling around Castlewood? Tell us what you need and when. No agents advertise here yet, so we’ll keep your request for up to 30 days and send it to local agents who join. No obligation, and you choose who to work with.
Loading map…
Shares ZIP codes with Claremont Colony and Poinsett Colony.
Town boundaries don’t always match ZIP codes: a ZIP code can cross into neighboring towns, and a town can share a ZIP code with its neighbors. Facts describe the town itself; market figures describe whole ZIP codes.