Best Internet Providers in Castlewood, SD
All 8 providers, ranked by coverage, speed and customer ratings
Find internet availability by address in Castlewood, SD
Castlewood has 8 internet service providers, they are sorted by coverage, available speed, and customer rating from our unbiased internet provider report. Cable, Fiber, Fixed Wireless, and DSL internet are available in the city. Reviews are grouped by provider and the type of service they offer, covering all 4 available internet technologies in Castlewood.
Ranks compare Castlewood with the 15,682 US towns of 1,000 to 9,999 people, the tiers of our fastest-cities rankings.
The Best Internet in Castlewood, SD at a Glance
Castlewood Internet Providers, Ranked by Coverage, Speed and Customer Ratings
ITC
Connection
Customer Rating
Fiber
Mediacom
Connection
Customer Rating
Cable
GigFire
Connection
Customer Rating
Fixed Wireless
Providers with less than 1% coverage in this city are excluded from the list. To see if one of these providers is available at your home, please use the address search above.
Speed and technology may vary by address for all providers. Please note we may have a financial relationship with some of the providers above, which does not impact the customer ratings displayed. Customer ratings listed above are national ratings, local Castlewood ratings may vary and are shown below.
Who is the Best Internet Provider in Castlewood, SD?
Interstate Telecommunications Cooperative is the highest-rated internet provider in Castlewood based on 27 South Dakota customer reviews, and T-Mobile Home Internet has the highest rating nationwide. The provider information above and the information immediately below can help you decide. Compare provider ratings and review counts above.
Which Providers are Available at my Home in Castlewood?
Coverage changes block by block. Pick a provider and a technology to see where its service reaches: the darker the area, the larger the share of homes it covers. For your exact address, use the address search above.
Coverage map for each provider in Castlewood
How Castlewood Compares to Places Its Size
Castlewood's report card score is in the bottom 50% and its connectivity index is in the top 35%.
| Measure | Castlewood | Rank among US towns of 1,000 to 9,999 people | Hamlin County | South Dakota | US | Leader |
|---|---|---|---|---|---|---|
| ISP Report Card inputs: what providers offer here | ||||||
| Fiber availability | 99.9% | top 7% | 99.6% | 79.0% | 71.5% | 1,056 places at 100.0% |
| Average top speed | 1,000 Mbps | bottom 35% | 1,000 Mbps | 2,675 Mbps | 3,486 Mbps | Collegedale, TN and Lakesite, TN and 2 more (25,000 Mbps) |
| Providers at a typical address | 3.7 | bottom 16% | 3.9 | 5.8 | 7.1 | McLendon-Chisholm, TX (14.2) |
| Connectivity index inputs: how much households need and use the internet | ||||||
| People per household | 2.8 | top 16% | 2.8 | 2.5 | 2.7 | St. George, GA (6.2) |
| Workers who work from home | 7% | bottom 34% | 7% | 10% | 15% | Indian Springs, NV (76%) |
| Homes with a computer, tablet or phone | 97% | top 19% | 97% | 94% | 96% | 515 places at 100% |
| Homes with internet | 86% | bottom 38% | 90% | 90% | 91% | 115 places at 100% |
| Homes on fiber, cable or DSL | 70% | top 41% | 66% | 76% | 76% | Bunkerville, NV and Fort Myer, VA and 3 more (100%) |
| More about the households here | ||||||
| Homes with a desktop or laptop | 83% | top 24% | 77% | 78% | 81% | 12 places at 100% |
| Median household income | $92,725 | top 25% | $84,832 | $80,420 | $93,246 | 16 places at $250,001 |
| Residents in school (6th grade to college) | 17% | top 12% | 15% | 15% | 16% | University Park, PA (95%) |
Fiber reaches 99.9% of homes in Castlewood, against 99.6% across Hamlin County and 79.0% across South Dakota. Households in Castlewood are larger than the US average (2.8 people against 2.7); 7% of workers work from home (US 15%); and the median household income is $92,725 (US $93,246).
Our demographic data is sourced from the latest 5-year release of the American Community Survey by the US Census Bureau.
Fiber, 5G, Cable and DSL Internet in Castlewood
Which Fiber Internet Providers are Available in Castlewood?
ITC Fiber in Castlewood, SD
Availability:
99.9%
Customer Rating:
(6)
Avg. Download Speed
1,000 Mbps
Interstate Telecommunications Cooperative offers Fiber service to 99.9% of Castlewood homes. Across the city, ITC Fiber is the only type of service available from the company, with speeds up to 1,000 Mbps
Which Fixed Wireless and LTE Internet Providers are Available in Castlewood?
GigFire Fixed Wireless in Castlewood, SD
Availability:
90.5%
Customer Rating:
(1)
Avg. Download Speed
150 Mbps
GigFire offers Fixed Wireless service to 90.5% of Castlewood homes. Across the city, GigFire Fixed Wireless is the only type of service available from the company, with speeds up to 150 Mbps
Verizon Fixed Wireless in Castlewood, SD
Availability:
51.5%
Customer Rating:
(362)
Avg. Download Speed
238 Mbps
Verizon offers Fixed Wireless service to 51.5% of Castlewood homes. Across the city, Verizon Fixed Wireless is the only type of service available from the company, with speeds up to 238 Mbps, with speeds from 25 Mpbs up to 300 Mbps depending on the address. Upload speeds differ from download speeds, and are as low 6.0 and as high as 20, with an average of 17 Mbps throughout the city.
T-Mobile Home Internet Fixed Wireless in Castlewood, SD
Availability:
34.7%
Customer Rating:
(342)
Avg. Download Speed
37 Mbps
T-Mobile Home Internet offers Fixed Wireless service to 34.7% of Castlewood homes. Across the city, T-Mobile Home Internet Fixed Wireless is the only type of service available from the company, with speeds up to 37 Mbps, with speeds from 25 Mpbs up to 100 Mbps depending on the address. Upload speeds differ from download speeds, and are as low 3.0 and as high as 20, with an average of 5.7 Mbps throughout the city.
EarthLink Fixed Wireless in Castlewood, SD
Availability:
11.0%
Customer Rating:
(4)
Avg. Download Speed
25 Mbps
EarthLink offers Fixed Wireless service to 11.0% of Castlewood homes. Across the city, EarthLink Fixed Wireless is the only type of service available from the company, with speeds up to 25 Mbps
AT&T Fixed Wireless in Castlewood, SD
Availability:
11.0%
Customer Rating:
(205)
Avg. Download Speed
25 Mbps
AT&T offers Fixed Wireless service to 11.0% of Castlewood homes. Across the city, AT&T Fixed Wireless is the only type of service available from the company, with speeds up to 25 Mbps
Midco Fixed Wireless in Castlewood, SD
Availability:
7.8%
Customer Rating:
(5)
Avg. Download Speed
100 Mbps
Midco offers Fixed Wireless service to 7.8% of Castlewood homes. Across the city, Midco Fixed Wireless is the only type of service available from the company, with speeds up to 100 Mbps
Which Cable Internet Providers are Available in Castlewood?
Mediacom Cable in Castlewood, SD
Availability:
62.2%
Customer Rating:
(82)
Avg. Download Speed
1,000 Mbps
Mediacom offers Cable service to 62.2% of Castlewood homes. Across the city, Mediacom Cable is the only type of service available from the company, with speeds up to 1,000 Mbps
Which DSL Internet Providers are Available in Castlewood?
According to the most recently submitted data by internet service providers to the FCC, there are currently no DSL providers available in Castlewood, SD.
Internet in Castlewood by Neighborhood and ZIP Code
Castlewood has 1 ZIP code with its own page. Each row links to that place’s page.
Neighborhoods in Castlewood
| Neighborhood | People | Homes with fiber | Average top speed | Providers at a typical address | Report card | Connectivity |
|---|
ZIP codes in Castlewood
| ZIP code | People | Homes with fiber | Average top speed | Providers at a typical address | Report card | Connectivity |
|---|---|---|---|---|---|---|
| 57223 | 1,427 | 99.9% | 1,000 Mbps | 3.7 | C+ | 57/100 |
How Castlewood Compares to Nearby Places
The 10 places nearest to Castlewood that have their own pages are all within 13 miles. Among them, Estelline has the most homes with fiber (98.6%) and Watertown the fewest (59.1%); Castlewood has 99.9%.
| Place | People | Homes with fiber | Average top speed | Providers at a typical address | Report card | Connectivity |
|---|---|---|---|---|---|---|
| Castlewood (this page) | 1,135 | 99.9% | 1,000 Mbps | 3.7 | C+ | 57/100 |
| Watertown | 23,517 | 59.1% | 3,401 Mbps | 7.7 | B | 44/100 |
| Estelline | 1,222 | 98.6% | 994 Mbps | 4.5 | C+ | 58/100 |
| Hayti | 899 | 100.0% | 1,000 Mbps | 3.9 | C+ | 50/100 |
| Goodwin | 567 | 100.0% | 1,000 Mbps | 2.2 | C | 46/100 |
| Lake Poinsett | 492 | 100.0% | 1,000 Mbps | 4.1 | C+ | 53/100 |
| Foley | 489 | 96.9% | 1,365 Mbps | 7.7 | B+ | 53/100 |
| Kranzburg | 463 | 98.1% | 1,293 Mbps | 4.8 | B- | 70/100 |
| Thomas | 190 | 98.4% | 1,000 Mbps | 3.3 | C+ | 60/100 |
| Kones Corner | 162 | 100.0% | 1,000 Mbps | 3.7 | C+ | 58/100 |
| Stone Bridge | 112 | 96.4% | 1,000 Mbps | 3.2 | C | 61/100 |
Who is the Fastest Internet Provider in Castlewood?
According to unbiased feedback from real internet customers, they reported being happiest with speeds provided by Interstate Telecommunications Cooperative. On the other hand, based on data provided by the internet providers to the FCC, Interstate Telecommunications Cooperative and Mediacom should have faster speeds at a local level. While we typically put more weight on real-world customer ratings, we display both satisfaction and technical maximum information for customers to decide for themselves.
Data Reported to FCC by ISPs: Average Maximum Available in Castlewood
| Interstate Telecommunications Cooperative | 1,000 |
|---|---|
| Mediacom | 1,000 |
| Verizon | 300 |
| GigFire | 150 |
| Viasat | 100 |
| T-Mobile Home Internet | 100 |
| Midco | 100 |
| HughesNet | 25 |
| AT&T | 25 |
| EarthLink | 25 |
How fast is your internet?
Test your connection here and see it next to the speeds providers advertise in Castlewood. It takes about 20 seconds and, on a fast line, can move a few hundred MB of data.
Customer Ratings for Castlewood Internet Providers
Based on 27 reviews from South Dakota internet customers, Interstate Telecommunications Cooperative is the best internet service provider for Castlewood residents. Interstate Telecommunications Cooperative was rated at an average of 4.50 out of 5 in our report for overall customer satisfaction. Mediacom wins for second-place in South Dakota, with 4.00 out of 5 stars and 62.2% coverage in Castlewood.
At a national level, based on 2360 national reviews for any of the providers listed above, T-Mobile Home Internet is rated higher than any other provider, with a rating of 4.02 out of 5.
Local, State, and National Ratings for all Castlewood Internet Providers
The table below shows average customer ratings from customers in Castlewood, South Dakota, and customers throughout the country.
| ISP / Tech Type | Castlewood Overall | South Dakota Overall | National Overall | For Service | ||
|---|---|---|---|---|---|---|
| ITC | (1) | (6) | (6) | View Plans | ||
| AT&T |  (0) |  (4) | (1051) | View Plans | ||
| Mediacom | (0) | (1) | (93) | View Plans | ||
| Verizon | (0) | (2) | (816) | View Plans | ||
| Midco | (0) | (14) | (36) | View Plans | ||
| HughesNet | (0) | (0) |  (25) | View Plans | ||
| T-Mobile Home Internet | (0) | (0) | (342) | View Plans | ||
| EarthLink | (0) | (0) | (15) | View Plans | ||
| GigFire | (0) | (0) | (1) | View Plans | ||
| Viasat | (0) | (0) |  (12) | View Plans |
Customer Ratings for Internet Provider Speeds in Castlewood
Based on data reported by Castlewood ISPs to the FCC, the fastest speeds in the city are available through Interstate Telecommunications Cooperative and Mediacom. These internet providers offer speeds up to 1,000 Mbps in Castlewood. Therefore, the average customer can get up to 1,000 Mbps if they’re willing to purchase the fastest subscription tier available at their homes.
Additionally, actual customers rated their satisfaction with internet speed highest with Interstate Telecommunications Cooperative. This indicates ITC reliably delivers speeds expected by the customer based on the plan they are paying for.
| ISP / Tech Type | Castlewood Speed | South Dakota Speed | National Speed | For Service | ||
|---|---|---|---|---|---|---|
| ITC | (1) | (6) | (6) | View Plans | ||
| AT&T | (0) | (4) | (1051) | View Plans | ||
| Verizon | (0) | (2) | (816) | View Plans | ||
| Mediacom | (0) | (1) | (93) | View Plans | ||
| Midco | (0) | (14) | (36) | View Plans | ||
| HughesNet | (0) | (0) | (25) | View Plans | ||
| T-Mobile Home Internet | (0) | (0) | (342) | View Plans | ||
| EarthLink | (0) | (0) | (15) | View Plans | ||
| GigFire | (0) | (0) |  (1) | View Plans | ||
| Viasat | (0) | (0) | (12) | View Plans |
Who is the Cheapest Internet Provider in Castlewood?
Of the providers in Castlewood, customers rate Verizon the best for price. Data comes from customers rating their satisfaction with pricing: in Castlewood where enough of them have reviewed a provider, otherwise across South Dakota or the country. This feedback is valuable because it considers price changes and whether the speeds paid for are worth it.
Verizon is rated 3.00 out of 5 for price, which is lower than the average across all internet providers in the country. Interstate Telecommunications Cooperative is rated second for affordability, with an average price rating of 3.50 out of 5.
The table below shows how customers in Castlewood, South Dakota, and the United States rated the affordability of their internet service.
Rated Affordability in Castlewood
| ISP / Tech Type | Castlewood Affordability | South Dakota Affordability | National Affordability | For Service | ||
|---|---|---|---|---|---|---|
| AT&T | (0) | (4) | (1051) | View Plans | ||
| ITC | (1) | (6) | (6) | View Plans | ||
| Mediacom | (0) | (1) | (93) | View Plans | ||
| Verizon | (0) | (2) | (816) | View Plans | ||
| Midco | (0) | (14) | (36) | View Plans | ||
| HughesNet | (0) | (0) | (25) | View Plans | ||
| T-Mobile Home Internet | (0) | (0) | (342) | View Plans | ||
| GigFire | (0) | (0) | (1) | View Plans | ||
| EarthLink | (0) | (0) | (15) | View Plans | ||
| Viasat | (0) | (0) | (12) | View Plans |
Customer Reviews for Internet Service Providers in South Dakota
Customer Reviews
ISPReports User
Midco Cable
October 02, 2026 Constant outages, and a lot more expensive than other providers.
A Brookings, SD Customer
Mediacom Cable
June 05, 2026 Brian M.
Bluepeak Fiber
June 01, 2026 The installation charge was too high and there are a lot of hidden fees and taxes.
Aaron M.
AT&T Fixed Wireless
May 29, 2026 My internet provider has been very reliable and consistent. I have used it on the go in many locations and it has rarely let me down. I am a very satisfied customer of AT&T and have nothing but praise for the service provided and the price point. I would highly recommend this service to everyone I know.
Dustin B.
Midco Fixed Wireless
April 14, 2026 They have good service, but their pricing is beyond sane. Basic cable runs $60 each room so to have basic cable in my home would cost $180. FOr basic cable. Basic non Wi Fi internet starts at $60 month. It's absolutely nuts how much it costs.
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Which ISP Should You Choose in Castlewood?
The right ISP for you depends upon your needs, but in general we can make the following suggestions:
- The best all-around internet service provider in Castlewood is ITC.
- The fastest internet provider should be Interstate Telecommunications Cooperative and Mediacom. Considering speed for the money and reliability in speeds, Interstate Telecommunications Cooperative may be a better choice based on real-world local customer feedback.
- The most affordable internet provider in Castlewood is Verizon.
- Viasat, Interstate Telecommunications Cooperative, and HughesNet has the broadest coverage in Castlewood, available to 99.9% of homes, and is most likely to cover your home. To find out exactly what’s available at your home, please use our address search tool.