Carrierlytics County Coverage Guide

Jefferson County, NY Cell Phone Coverage Map & Network Rankings (2026)

Find the best cell phone network and plan to use in Jefferson County, NY.

Using FCC mobile coverage data across cities and ZIP codes in Jefferson County, NY, Carrierlytics compares the top-performing networks and the cheapest plans that use them.

Jefferson County, NY

Cell phone coverage map for Jefferson County, NY

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 Carrierlytics.

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Cell phone coverage rankings by network in Jefferson County, NY

#1

Verizon

Coverage Score 69.1
In Jefferson County, NY
Overall
94.0%
4G LTE
94.0% avg. -94 dBm 4G LTE signal where 4G LTE coverage exists: avg. -94 dBm
5G
42.2% avg. -93 dBm 5G signal where 5G coverage exists: avg. -93 dBm
Fast 5G
27.2% avg. -89 dBm Fast 5G signal where Fast 5G coverage exists: avg. -89 dBm
#2

AT&T

Coverage Score 66.6
In Jefferson County, NY
Overall
94.4%
4G LTE
94.4% avg. -106 dBm 4G LTE signal where 4G LTE coverage exists: avg. -106 dBm
5G
64.7% avg. -112 dBm 5G signal where 5G coverage exists: avg. -112 dBm
Fast 5G
43.6% avg. -110 dBm Fast 5G signal where Fast 5G coverage exists: avg. -110 dBm
#3

T-Mobile

Coverage Score 61.7
In Jefferson County, NY
Overall
58.1%
4G LTE
58.0% avg. -97 dBm 4G LTE signal where 4G LTE coverage exists: avg. -97 dBm
5G
51.5% avg. -91 dBm 5G signal where 5G coverage exists: avg. -91 dBm
Fast 5G
33.0% avg. -86 dBm Fast 5G signal where Fast 5G coverage exists: avg. -86 dBm
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Coverage by city in Jefferson County, NY

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

City Verizon AT&T T-Mobile
Adams, NY 100.0% 100.0% 100.0% 81.3% 100.0% 100.0% 87.5% 75.0% 87.5% 87.5% 68.8% 25.0%
Adams Center, NY 100.0% 100.0% 43.8% 11.6% 100.0% 100.0% 97.3% 75.0% 89.3% 89.3% 81.3% 49.1%
Alexandria Bay, NY 100.0% 100.0% 100.0% 94.1% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0%
Antwerp, NY 100.0% 100.0% 100.0% 87.0% 100.0% 100.0% 100.0% 87.0% 100.0% 100.0% 100.0% 100.0%
Belleville, NY 100.0% 100.0% 21.4% 0.0% 100.0% 100.0% 28.6% 28.6% 50.0% 50.0% 14.3% 0.0%
Black River, NY 100.0% 100.0% 77.8% 55.6% 100.0% 100.0% 100.0% 97.8% 100.0% 100.0% 100.0% 100.0%
Brownville, NY 100.0% 100.0% 78.6% 57.1% 100.0% 100.0% 100.0% 35.7% 100.0% 100.0% 100.0% 71.4%
Calcium, NY 100.0% 100.0% 90.8% 64.6% 99.2% 99.2% 96.2% 44.6% 100.0% 100.0% 100.0% 100.0%
Cape Vincent, NY 100.0% 100.0% 100.0% 94.1% 100.0% 100.0% 100.0% 100.0% N/A N/A N/A N/A
Carthage, NY 100.0% 100.0% 0.0% 0.0% 100.0% 100.0% 96.4% 81.8% 100.0% 100.0% 100.0% 90.9%
Chaumont, NY 100.0% 100.0% 100.0% 95.2% 100.0% 100.0% 100.0% 100.0% 4.8% 4.8% 0.0% 0.0%
Clayton, NY 100.0% 100.0% 91.2% 79.4% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 97.1%
Deferiet, NY 93.3% 93.3% 0.0% 0.0% 100.0% 100.0% 93.3% 53.3% 26.7% 26.7% 6.7% 6.7%
Depauville, NY 100.0% 100.0% 79.6% 53.0% 99.6% 98.7% 96.5% 44.3% 4.3% 4.3% 2.2% 0.0%
Dexter, NY 100.0% 100.0% 100.0% 85.7% 100.0% 100.0% 100.0% 92.9% 100.0% 100.0% 100.0% 100.0%
Ellisburg, NY 100.0% 100.0% 66.7% 54.2% 100.0% 100.0% 45.8% 37.5% 33.3% 33.3% 12.5% 0.0%
Evans Mills, NY 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0%
Felts Mills, NY 100.0% 100.0% 0.0% 0.0% 100.0% 100.0% 100.0% 69.2% 100.0% 100.0% 100.0% 69.2%
Fishers Landing, NY 100.0% 100.0% 100.0% 63.6% 81.8% 81.8% 81.8% 81.8% 81.8% 81.8% 81.8% 81.8%
Fort Drum, NY 100.0% 100.0% 82.1% 56.1% 100.0% 100.0% 100.0% 80.0% 98.5% 98.5% 96.1% 84.5%
Glen Park, NY 100.0% 100.0% 93.8% 87.5% 100.0% 100.0% 100.0% 75.0% 100.0% 100.0% 100.0% 100.0%
Great Bend, NY 100.0% 100.0% 61.0% 47.8% 100.0% 100.0% 96.3% 80.1% 96.3% 95.6% 93.4% 81.6%
Henderson, NY 100.0% 100.0% 0.0% 0.0% 100.0% 100.0% 91.7% 91.7% 25.0% 25.0% 8.3% 0.0%
Henderson Harbor, NY 100.0% 100.0% 10.0% 4.0% 100.0% 100.0% 98.0% 90.0% 10.0% 10.0% 8.0% 2.0%
Herrings, NY 100.0% 100.0% 0.0% 0.0% 100.0% 100.0% 66.7% 0.0% 33.3% 33.3% 33.3% 0.0%
La Fargeville, NY 100.0% 100.0% 75.7% 51.4% 100.0% 100.0% 64.9% 52.7% 89.2% 89.2% 77.0% 37.8%
Lorraine, NY 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 0.0% 0.0% N/A N/A N/A N/A
Mannsville, NY 100.0% 100.0% 100.0% 70.0% 100.0% 100.0% 100.0% 95.0% 100.0% 100.0% 100.0% 100.0%
Natural Bridge, NY 100.0% 100.0% 33.3% 16.7% 100.0% 100.0% 100.0% 96.7% 100.0% 100.0% 100.0% 90.0%
Oxbow, NY 100.0% 100.0% 0.0% 0.0% 100.0% 100.0% 87.5% 75.0% N/A N/A N/A N/A
Pamelia Center, NY 100.0% 100.0% 100.0% 96.6% 100.0% 100.0% 100.0% 93.1% 100.0% 100.0% 100.0% 100.0%
Philadelphia, NY 100.0% 100.0% 61.9% 42.9% 100.0% 100.0% 9.5% 4.8% 100.0% 100.0% 100.0% 100.0%
Pierrepont Manor, NY 100.0% 100.0% 41.2% 23.5% 100.0% 100.0% 58.8% 41.2% 94.1% 94.1% 88.2% 35.3%
Plessis, NY 100.0% 100.0% 37.5% 0.0% 100.0% 100.0% 100.0% 50.0% 100.0% 100.0% 100.0% 12.5%
Redwood, NY 100.0% 100.0% 90.9% 72.7% 100.0% 100.0% 95.5% 65.9% 100.0% 100.0% 93.2% 45.5%
Rodman, NY 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% N/A N/A N/A N/A
Sackets Harbor, NY 100.0% 100.0% 98.1% 90.4% 100.0% 100.0% 55.8% 51.9% 98.1% 98.1% 98.1% 98.1%
Theresa, NY 100.0% 100.0% 0.0% 0.0% 96.7% 96.7% 33.3% 0.0% 93.3% 93.3% 53.3% 10.0%
Thousand Island Park, NY 100.0% 100.0% 62.5% 25.0% 100.0% 100.0% 87.5% 87.5% 100.0% 100.0% 75.0% 50.0%
Three Mile Bay, NY 100.0% 100.0% 0.0% 0.0% 100.0% 100.0% 33.3% 0.0% N/A N/A N/A N/A
Watertown, NY 100.0% 100.0% 92.2% 80.0% 100.0% 100.0% 100.0% 68.3% 100.0% 100.0% 99.5% 94.1%
Wellesley Island, NY 100.0% 100.0% 52.0% 30.2% 97.9% 97.9% 65.8% 58.4% 60.5% 60.5% 49.1% 19.9%
West Carthage, NY 100.0% 100.0% 0.0% 0.0% 100.0% 100.0% 100.0% 93.3% 100.0% 100.0% 96.7% 76.7%

About The Coverage Data

Coverage and signal estimates are derived by Carrierlytics 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 Jefferson County, NY 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.