In Castlewood there is 1 residential Fiber provider covering 99.91% of the city. The average home can get speeds up to 1,000 Mbps. Note that we may have a financial relationship with some of the providers below. This does not influence rankings, and helps us provide high-quality detailed information for free.
This page contains all Fiber internet providers in Castlewood, SD.
To see availability maps for all providers including fiber, cable, DSL, and more in Castlewood, SD please click below.
Castlewood, SD Availability Maps
Fiber Internet Service Provider in Castlewood
Data updated 11/14/2025, based on FCC data from 12/31/2024. This is the most current data available as of .
To avoid wasting your time, providers with less than 1% coverage in Castlewood are not shown.
Castlewood Satellite TV & Internet Providers
DISH Satellite TV
DIRECTV Satellite TV
Not sure whether to choose Dish or DIRECTV? For most people most of the time we recommend DISH. But click here to learn more.
Viasat Satellite Internet
Where in Castlewood is fiber internet available?
Fiber Internet Availability Key
Fiber is available in 99.91% of Castlewood. Areas in green have fiber internet service, where areas in yellow or red may not. The most widely available provider is ITC. Call one of the companies with service in Castlewood above to see who has service at your home.
How fast is fiber internet in Castlewood?
The map below shows maximum fiber internet speeds by area in Castlewood.
Fiber Internet Speed Key
The average Castlewood home can get up to 1,000 Mbps on their fiber internet plan. The fastest fiber download speed in the city is 1,000 Mbps, which 99.91% of residents can get.
Is fiber the fastest internet I can get in Castlewood?
The fastest internet for you may vary based on where in Castlewood you live. In general, satellite competes most often with fiber in the city.
- Fiber is the fastest internet type for 99.91% of Castlewood homes.
- Cable is fastest for less than 1% of the city.
- DSL is fastest for less than 1%.
- Fixed wireless is fastest for less than 1%.
- Satellite internet may be the only option for less than 1% of Castlewood homes.
Fiber Providers in Depth
Below you'll find which TV and internet providers offer service in Castlewood, along with details on where in Castlewood and at what speeds.
Interstate Telecommunications Cooperative Fiber in Castlewood, SD
ITC fiber coverage
About 99.91%, or 1,134 people, have ITC fiber internet available to them in the city. The company covers the entire Castlewood area. ITC is a large internet service provider internet service providers in the US, with internet service available in most of Castlewood.
Interstate Telecommunications Cooperative fiber download speeds
ITC is one of the fastest when comparing download speeds to all other internet providers in Castlewood. Versus other fiber providers in the area, ITC fiber is the fastest. There are no different maximum speeds throughout Castlewood. The fastest plan anyone in Castlewood can order from ITC goes up to 1,000 Mbps, and all Castlewood customers can get this speed.
Show all download speeds
- 100.0% up to 1,000.0 Mbps
Interstate Telecommunications Cooperative fiber upload speeds
In Castlewood download speeds tend to be equal to than upload speeds for ITC fiber. Compared to other ISPs, ITC is the fastest where upload speeds are concerned, and the fastest compared to other Castlewood fiber providers. ITC offers no different upload speeds across the city. The fastest upload speed available to anyone from this ISP in Castlewood is up to 1,000 Mbps, which is available to everyone covered.
Show all upload speeds
- 100.0% up to 1,000.0 Mbps
Castlewood Fiber by Area
This information is most helpful to those looking for homes or considering moving to Castlewood or any of the areas nearby.
How does fiber internet in Castlewood compare to the rest of South Dakota?
Fiber internet speeds in Castlewood are much faster versus the average speeds in South Dakota: 0.00 Mbps in South Dakota versus 1,000 Mbps in the city. The state has similar fiber availability compared to the city. Average fiber coverage in South Dakota is 0.00% versus 99.91% in Castlewood.
What zip codes have fiber internet?
Fiber internet coverage varies by zip code and neighborhood. Some examples in or around Castlewood are shown below. You can enter any zip code here to see TV and internet providers by zip code.
What does fiber internet look like in other cities?
Below are cities nearby and with similar populations. This comparison can be useful if living somewhere with fast internet is important to you.
Nearby Cities
- Kones Corner, SD: more fiber coverage, similar speeds
- Stone Bridge, SD: less fiber coverage, similar speeds
- Estelline, SD: less fiber coverage, similar speeds
- Thomas, SD: less fiber coverage, similar speeds
- Goodwin, SD: more fiber coverage, similar speeds
- Hayti, SD: more fiber coverage, similar speeds
- Lake Poinsett, SD: more fiber coverage, similar speeds
- Foley, SD: less fiber coverage, similar speeds
- Kranzburg, SD: less fiber coverage, faster speeds
- Watertown, SD: less fiber coverage, faster speeds
Cities with Similar Populations
- Dover Beaches South, NJ: less fiber coverage, faster speeds
- Walhonding, OH: less fiber coverage, similar speeds
- Waterford, VT: less fiber coverage, similar speeds
- Faucett, MO: less fiber coverage, similar speeds
- Waynoka, OK: less fiber coverage, similar speeds
- Endeavor, WI: less fiber coverage, similar speeds
- Elwood, KS: less fiber coverage, similar speeds
- East Victor, NY: less fiber coverage, faster speeds
- Dysart, PA: less fiber coverage, faster speeds
- Wagners Lake, NE: less fiber coverage, similar speeds