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Thornton, CO Area Codes

Thornton, Colorado (population 147,766) uses area codes 303, 720 and 983.

Area code303
Area code720
Area code983
Time zoneMountain
Local time now…

Thornton has no telephone exchange of its own in NANPA records; it is served by the Denver exchange about 18.4 km away.

ThorntonDenverAuroraLakewoodArvadaWestminsterCentennialBoulderLongmontBroomfieldCommerce CityLittletonBrightonThornton
Thornton and nearby cities in area code 303

Carriers with Thornton numbers

1447 prefixes are assigned to the Denver exchange: 28% mobile, 26% VoIP and cable, 46% landline.

CarrierPrefixes
Lumen (Qwest)528
T-Mobile163
AT&T Mobility119
Verizon Wireless118
Lumen (Level 3)111
Verizon Business (MCImetro)80
AT&T (Teleport)59
Onvoy (Sinch)57

Area codes used in Thornton

Area codePrefixes serving ThorntonMain carriers in this code
303736Lumen (Qwest), Verizon Wireless, Lumen (Level 3)
720679T-Mobile, Lumen (Qwest), AT&T Mobility
98332Onvoy (Sinch), Wide Voice, AT&T Mobility

Thornton phone number prefixes

Numbers starting with these first six digits were originally assigned to the Denver exchange.

Nearby cities in area code 303

Questions

What is the area code for Thornton, CO?
Thornton uses 3 area codes: 303, 720 and 983. They overlay each other, so all of them cover the whole city and you dial 10 digits for local calls.
What time zone is Thornton in?
Thornton is in the Mountain time zone.