Union County, SD Cell Phone Coverage Map & Network Rankings (2026)

Find the best cell phone network and plan to use in Union County, SD

Coverage rankings for Union County, SD

T-Mobile currently ranks first for coverage in this area, with a coverage score of 91.7. Compare Wireless Carriers uses FCC broadband map data to estimate and calculate coverage scores. More on that further below.

RankCarrierScoreOverall4G LTE5GFast 5GAverage Signal
1T-Mobile91.794.9%94.9%89.0%76.1% -87 dBm
2AT&T83.695.9%95.3%79.0%67.4% -109 dBm
3Verizon76.099.0%99.0%46.8%33.9% -94 dBm

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

Cell phone coverage map for Union County, SD

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 Union County, SD

#1

T-Mobile

Coverage Score 91.7
In Union County, SD
Overall
94.9%
4G LTE
94.9%
5G
89.0%
Fast 5G
76.1%
Average Signal -87 dBm
#2

AT&T

Coverage Score 83.6
In Union County, SD
Overall
95.9%
4G LTE
95.3%
5G
79.0%
Fast 5G
67.4%
Average Signal -109 dBm
#3

Verizon

Coverage Score 76.0
In Union County, SD
Overall
99.0%
4G LTE
99.0%
5G
46.8%
Fast 5G
33.9%
Average Signal -94 dBm
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Coverage by city in Union County, SD

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

CityVerizonAT&TT-Mobile
Alcester, SD 100.0% 100.0% 92.9% 64.3% -88 dBm 100.0% 100.0% 100.0% 100.0% -103 dBm 100.0% 100.0% 100.0% 100.0% -80 dBm
Beresford, SD 100.0% 100.0% 93.0% 88.4% -80 dBm 100.0% 100.0% 97.7% 97.7% -117 dBm 100.0% 100.0% 100.0% 100.0% -68 dBm
Dakota Dunes, SD 100.0% 100.0% 95.2% 73.0% -89 dBm 100.0% 100.0% 100.0% 96.8% -98 dBm 100.0% 100.0% 100.0% 100.0% -72 dBm
Elk Point, SD 100.0% 100.0% 100.0% 100.0% -76 dBm 100.0% 100.0% 100.0% 100.0% -94 dBm 100.0% 100.0% 100.0% 100.0% -83 dBm
Jefferson, SD 100.0% 100.0% 84.6% 30.8% -92 dBm 100.0% 100.0% 100.0% 100.0% -88 dBm 100.0% 100.0% 100.0% 100.0% -64 dBm
North Sioux City, SD 100.0% 100.0% 97.6% 94.0% -82 dBm 100.0% 100.0% 100.0% 97.6% -100 dBm 100.0% 100.0% 100.0% 100.0% -72 dBm
Richland, SD 100.0% 100.0% 31.4% 27.9% -95 dBm 99.3% 99.3% 77.1% 60.0% -117 dBm 94.3% 94.3% 85.0% 67.1% -94 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 Union County, SD 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.