Fiber is actively arriving in Jefferson County. It reached 965 more locations here in the last twelve months. Check whether your own address is inside a build before committing to anything with a contract.
Everything below comes from the FCC's Broadband Data Collection, the filings providers are legally required to make about where they offer service. It describes the county; your own address can differ, and that is exactly why the technology mix matters.
Where Jefferson County sits in Illinois
Share of addresses with no fixed broadband at 25/3 Mbps
0.0% to 2.7%
2.7% to 4.2%
4.2% to 5.0%
5.0% to 7.0%
7.0% to 9.7%
9.7% to 13%
13% and above
not published
This county is outlined. Darker means a larger share of addresses with no fixed broadband. Select any county to open it.
What reaches homes in Jefferson County
Locations covered by each technology, out of 17,382 broadband serviceable locations. An address can be reached by more than one technology, so these add up to more than 100%.
Fiber7,857 · 45%
Cable9,469 · 54%
Licensed fixed wireless12,038 · 69%
Unlicensed fixed wireless6,418 · 37%
DSL over copper0 · 0.0%
Served, underserved, unserved
The FCC's three categories. "Served" means at least 100/20 Mbps is available; "underserved" means at least 25/3 but below 100/20; "unserved" means below 25/3 or nothing at all.
Category
Locations
Share of county
Served
15,440
88.8%
Underserved
726
4.2%
Unserved
1,216
7.0%
What that means if you live here
The USDA classes Jefferson County as a nonmetro county with an urban population of 5,000 to 20,000, not adjacent to a metro area (continuum code 7).
Population is around 36,877, which works out to about 2.1 people for every address on the list.
1,216 locations, 7.0% of the county, have nothing that reaches 25/3 Mbps.
A further 4.2% of the county sits in the middle: served, but below the 100/20 Mbps mark.
The most widely available technology here is licensed fixed wireless, reaching 12,038 locations (69.3%); next is cable at 54.5%.
Fiber reaches 7,857 locations, 45.2% of the county.
12,038 locations are within reach of licensed fixed wireless, 69.3% of the total, and no other technology here reaches further.
Cable reaches 54.5% of locations, more than fiber does, and it will be concentrated in the built-up parts of the county.
16 providers file coverage in Jefferson County: 5 with fiber, 1 with cable, 4 with licensed fixed wireless.
In twelve months fiber went from 6,892 locations to 7,857 here.
Served locations rose 5.21% year on year.
Jefferson County is harder-served than the typical Illinois county, where the median unserved share is 4.6%.
Fiber lags the rest of Illinois, where the median county is at 58.4%.
What people actually measure in Illinois
Median of real speed tests run on each network during 2024, from M-Lab. This is measured performance, not an advertised plan speed, and not a customer review. The middle-half column shows how consistent a network is: a wide spread means your experience depends heavily on where and when.
Network
Median download
Middle half of tests
Median upload
Latency
Tests
Comcast Cable Communications
152 Mbps
56.6 Mbps to 321 Mbps
21.3 Mbps
8 ms
531,546
AT&T Enterprises
80.0 Mbps
27.8 Mbps to 262 Mbps
19.2 Mbps
6 ms
143,769
Verizon Business
36.9 Mbps
10.3 Mbps to 101 Mbps
6.3 Mbps
27 ms
102,625
ZSCALER
70.8 Mbps
22.7 Mbps to 148 Mbps
20.2 Mbps
1 ms
79,047
RCN
146 Mbps
37.6 Mbps to 337 Mbps
23.3 Mbps
7 ms
50,139
Charter Communications
152 Mbps
69.3 Mbps to 315 Mbps
11.0 Mbps
14 ms
29,193
Mediacom Communications
117 Mbps
50.9 Mbps to 308 Mbps
26.0 Mbps
12 ms
24,579
Metronet
137 Mbps
67.1 Mbps to 307 Mbps
101 Mbps
22 ms
15,878
ITV-3
196 Mbps
72.2 Mbps to 373 Mbps
136 Mbps
8 ms
9,002
CABLE ONE
125 Mbps
57.1 Mbps to 279 Mbps
29.0 Mbps
17 ms
7,199
Cellular networks, measured
The same measurement for the mobile networks behind 5G home internet. These tests come from phones as well as home gateways, so treat them as an indication of network health in the state rather than a home-internet plan speed.
Network
Median download
Middle half of tests
Median upload
Latency
Tests
T-Mobile USA
51.9 Mbps
12.8 Mbps to 142 Mbps
8.5 Mbps
23 ms
115,353
Latency is the number that decides whether video calls and gaming feel right, and it is where satellite differs most from everything else. Measured data is statewide: below county level there are usually too few tests to report an honest number.
Disclosure: some links on this page are affiliate links. If you sign up for a service or buy equipment through one, we may earn a commission at no extra cost to you. It never changes which options we list or the order we rank them in, and we do not accept payment for a better placement.
Your realistic options in Jefferson County
Fiber
Fiber, if it has reached you
The best outcome by a distance: symmetric speed, low latency, no weather sensitivity, no data ceiling in practice.
Best for
Anyone whose address is inside a fiber build. Always check this first.
Watch out
Coverage stops abruptly at the edge of a build. Being a mile from fiber is the same as being fifty.
5G home internet
T-Mobile Home Internet
Home internet over T-Mobile’s cellular network. A gateway box you plug in yourself; no truck roll, no dish.
Best for
Rural addresses that still get a usable T-Mobile signal, often near a highway or a town
Watch out
Availability is decided address by address, not by town. Speed varies with how busy the local tower is.