Grundy County, IL Cell Phone Coverage Map & Network Rankings (2026)

Find the best cell phone network and plan to use in Grundy County, IL

Coverage rankings for Grundy County, IL

T-Mobile currently ranks first for coverage in this area, with a coverage score of 89.9. Compare Wireless Carriers uses FCC broadband map data to estimate and calculate coverage scores. More on that further below.

RankCarrierScoreOverall4G LTE5GFast 5GAverage Signal
1T-Mobile89.994.5%94.5%88.5%69.9% -89 dBm
2Verizon88.8100.0%100.0%82.7%58.9% -93 dBm
3AT&T88.699.6%99.6%92.7%80.1% -113 dBm

Scores include coverage area, network type, and average signal strength.

Cell phone coverage map for Grundy County, IL

Zoom in for local detail. Tap or click a colored area to see coverage and signal details. On mobile, use two fingers to move the map.

Coverage Key
Less covered More covered
Darker areas mean the carrier covers more of that location.

Map data © OpenStreetMap contributors, © CARTO. Rendered with MapLibre. FCC BDC mobile coverage processed by Compare Wireless Carriers.

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Cell phone coverage by network in Grundy County, IL

#1

T-Mobile

Coverage Score 89.9
In Grundy County, IL
Overall
94.5%
4G LTE
94.5%
5G
88.5%
Fast 5G
69.9%
Average Signal -89 dBm
#2

Verizon

Coverage Score 88.8
In Grundy County, IL
Overall
100.0%
4G LTE
100.0%
5G
82.7%
Fast 5G
58.9%
Average Signal -93 dBm
#3

AT&T

Coverage Score 88.6
In Grundy County, IL
Overall
99.6%
4G LTE
99.6%
5G
92.7%
Fast 5G
80.1%
Average Signal -113 dBm
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Coverage by city in Grundy County, IL

Cities and towns are shown for county-level comparison. Coverage percentages use land-area only coverage.

CityVerizonAT&TT-Mobile
Carbon Hill, IL 100.0% 100.0% 100.0% 100.0% -97 dBm 100.0% 100.0% 100.0% 100.0% -100 dBm 100.0% 100.0% 100.0% 100.0% -77 dBm
Coal City, IL 100.0% 100.0% 100.0% 98.6% -90 dBm 100.0% 100.0% 100.0% 94.9% -103 dBm 98.6% 98.6% 98.6% 97.8% -81 dBm
Diamond, IL 100.0% 100.0% 100.0% 100.0% -75 dBm 100.0% 100.0% 100.0% 97.8% -100 dBm 100.0% 100.0% 100.0% 100.0% -75 dBm
East Brooklyn, IL 100.0% 100.0% 100.0% 100.0% -90 dBm 100.0% 100.0% 0.0% 0.0% -110 dBm 100.0% 100.0% 100.0% 0.0% -100 dBm
Gardner, IL 100.0% 100.0% 100.0% 100.0% -84 dBm 100.0% 100.0% 90.7% 90.7% -118 dBm 100.0% 100.0% 100.0% 90.7% -86 dBm
Kinsman, IL 100.0% 100.0% 0.0% 0.0% -90 dBm 100.0% 100.0% 100.0% 100.0% -120 dBm N/A N/A N/A N/A N/A
Mazon, IL 100.0% 100.0% 100.0% 100.0% -73 dBm 100.0% 100.0% 100.0% 100.0% -105 dBm 100.0% 100.0% 100.0% 80.0% -91 dBm
Minooka, IL 100.0% 100.0% 99.1% 95.6% -85 dBm 100.0% 100.0% 99.6% 98.7% -107 dBm 100.0% 100.0% 100.0% 99.1% -77 dBm
Morris, IL 100.0% 100.0% 85.7% 69.5% -88 dBm 100.0% 100.0% 96.8% 87.7% -108 dBm 100.0% 100.0% 100.0% 93.8% -85 dBm
Seneca, IL 100.0% 100.0% 75.2% 62.4% -89 dBm 97.9% 97.9% 87.9% 67.4% -109 dBm 90.8% 90.8% 80.9% 64.5% -87 dBm
South Wilmington, IL 100.0% 100.0% 100.0% 100.0% -81 dBm 100.0% 100.0% 76.9% 76.9% -118 dBm 100.0% 100.0% 100.0% 84.6% -87 dBm
Verona, IL 100.0% 100.0% 40.0% 0.0% -100 dBm 100.0% 100.0% 100.0% 100.0% -112 dBm 40.0% 40.0% 40.0% 0.0% -100 dBm
Braceville, IL 100.0% 100.0% 100.0% 94.8% -92 dBm 100.0% 100.0% 98.7% 97.4% -112 dBm 100.0% 100.0% 100.0% 98.7% -76 dBm
Braidwood, IL 100.0% 100.0% 100.0% 96.2% -91 dBm 100.0% 100.0% 100.0% 97.7% -96 dBm 100.0% 100.0% 100.0% 100.0% -77 dBm
Channahon, IL 100.0% 100.0% 100.0% 97.8% -87 dBm 100.0% 100.0% 98.3% 87.8% -106 dBm 99.3% 99.3% 99.0% 94.5% -81 dBm
Dwight, IL 100.0% 100.0% 97.9% 88.7% -87 dBm 100.0% 100.0% 100.0% 100.0% -95 dBm 100.0% 100.0% 100.0% 87.6% -88 dBm
Godley, IL 100.0% 100.0% 100.0% 92.6% -93 dBm 100.0% 100.0% 100.0% 96.3% -109 dBm 100.0% 100.0% 100.0% 81.5% -86 dBm

About The Coverage Data

Coverage and signal estimates are derived by Compare Wireless Carriers from carrier-reported data in the FCC’s National Broadband Coverage Map, last updated in June 2025. “Percent covered” shows how much of the city or ZIP code area has a carrier signal, whether weak or strong. Signal bars show the estimated average signal strength in areas of Grundy County, IL where that carrier has coverage.

If a carrier says you should have service but you do not, run a challenge test with the FCC Mobile Speed Test App. The FCC uses those results to check carrier-submitted coverage data and requires a carrier response when enough tests show a pattern of inaccurate coverage reporting.