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Area Code 303 Location & Details

State / Region: Colorado • Country: United States

Major Cities Covered: Denver, Aurora, Lakewood, Thornton, Arvada, Westminster, Centennial, Boulder, Longmont, Castle Rock

Standard Dial Format
+1 (303) XXX-XXXX
Country Code: +1 (NANP Format)
What State is Area Code 303?
ColoradoState Hub →
Country Territory
United States
303 Area Code Time Zone
Mountain
303 Overlay Codes
720, 983

Area Code 303 Geographic Map

Interactive location bounds and coverage area for Colorado (Mountain Timezone)

Lat: 39.81° • Lng: -105.01°
📍 Geographic Center: ColoradoMap data © OpenStreetMap contributors

Where is Area Code 303 Located?

Telephone area code 303 is assigned to Colorado in United States. It serves cities and metropolitan communities including Denver, Aurora, Lakewood, Thornton, Arvada, Westminster, Centennial, Boulder, Longmont, Castle Rock.

Historical Context & Area Code Overlay Information:303 serves Colorado (United States).

For local and long-distance calls within area code 303, standard 10-digit dialing (303) XXX-XXXX applies.

Who Called Me from Area Code 303?

Received an unknown call, missed call, or text scam from area code 303? Here is how to trace who is calling from 303 area code and verify unknown numbers safely:

1.
Identify Missed Calls & Voicemails:

Legitimate contacts usually leave a detailed voicemail or caller ID record.

2.
Watch Out for Neighbor Spoofing:

Robocallers often fake incoming caller ID numbers using your local 303 prefix to boost pick-up rates.

3.
Reverse Phone Lookup Area Code 303:

Search public white-pages or use caller intelligence guides before returning unfamiliar calls.

Learn How Reverse Phone Lookups Work→

How to Call Area Code 303 & Dialing Format

When placing a phone call to a number in area code 303, follow the correct dialing format depending on your calling location:

  • Calling from inside the US / Canada (+1): Dial 1 + (303) + 7-digit number.
  • Calling from an international location outside +1: Dial your country's international exit code (e.g. 011 in US or + on mobile) + 1 + 303 + 7-digit number.
  • Do I need to dial area code 303 for local calls? Yes, 10-digit dialing (area code + line number) is mandatory across North American telephone networks.

Top Cities & Municipalities Served in Area Code 303

Urban centers, census places, and communities within the +1-303 calling area

50 Major Cities Listed
City NameCountyPopulation% of 303 Pop
DenverDenver County740,61326.8%
AuroraDenver County410,05314.8%
LakewoodJefferson County156,9275.7%
ThorntonBroomfield County147,7665.3%
ArvadaBroomfield County122,9014.4%
WestminsterBroomfield County116,1824.2%
CentennialDenver County108,6583.9%
BoulderBoulder County105,6893.8%
LongmontBroomfield County100,1093.6%
Castle RockDouglas County83,8153.0%
BroomfieldBroomfield County79,1742.9%
Commerce CityDenver County72,3452.6%
ParkerDouglas County65,9852.4%
LittletonDenver County46,2461.7%
BrightonDenver County45,3951.6%
ErieBroomfield County40,9041.5%
NorthglennBroomfield County38,8931.4%
EnglewoodDenver County35,3051.3%
Wheat RidgeBroomfield County32,0811.2%
LafayetteBroomfield County30,1161.1%

Counties Covered by Area Code 303

Geographic county distribution and population coverage across Colorado

County NameTotal Population% of 303 Area% of County
Denver County741,59154.5%100%
Broomfield County78,40328.0%100%
Jefferson County580,3596.5%31%
Douglas County393,0516.5%46%
Boulder County329,4853.9%33%
Arapahoe County675,7600.2%1%
Adams County549,2570.1%1%
Gilpin County5,9550.1%69%
Clear Creek County9,0230.1%17%

☎️Area Code 303 Exchange Prefixes & Carriers

Showing 50 of 800 central office 3-digit prefixes and assigned telecom carriers

81% Landline17% Wireless2% VoIP
PrefixLine UsageRate CenterAssigned CarrierAssign Date
(303) 200-📞LandlineDENVERTELEPORT COMMUNICATIONS AMERICA, LLC - CON/A
(303) 201-📞LandlineDENVERSPOK, INC.N/A
(303) 202-📞LandlineDENVERQWEST CORPORATIONN/A
(303) 203-📞LandlineDENVERAMERICAN MESSAGING SERVICES, LLCN/A
(303) 204-📱WirelessDENVERCELLCO PARTNERSHIP DBA VERIZON WIRELESS - CON/A
(303) 205-📞LandlineDENVERQWEST CORPORATIONN/A
(303) 206-📞LandlineDENVERSPOK, INC.N/A
(303) 207-📞LandlineDENVERSPOK, INC.N/A
(303) 208-📞LandlineDENVERSPOK, INC.N/A
(303) 209-📞LandlineDENVERMCIMETRO ACCESS TRANSMISSION SERVICES LLCN/A
(303) 210-📱WirelessDENVERT-MOBILE USA, INC.N/A
(303) 211-📞LandlineXXXXXXXXXXMULTIPLE OCN LISTINGN/A
(303) 212-📞LandlineDENVERAMERICAN MESSAGING SERVICES, LLCN/A
(303) 213-📞LandlineDENVERSPOK, INC.N/A
(303) 214-📞LandlineDENVERMCIMETRO ACCESS TRANSMISSION SERVICES LLCN/A
(303) 215-📞LandlineDENVERQWEST CORPORATIONN/A
(303) 216-📞LandlineDENVERQWEST CORPORATIONN/A
(303) 217-📞LandlineDENVERMCIMETRO ACCESS TRANSMISSION SERVICES LLCN/A
(303) 218-📞LandlineDENVERMCIMETRO ACCESS TRANSMISSION SERVICES LLCN/A
(303) 219-📞LandlineDENVERMCIMETRO ACCESS TRANSMISSION SERVICES LLCN/A
(303) 220-📞LandlineDENVERQWEST CORPORATIONN/A
(303) 221-📞LandlineDENVERQWEST CORPORATIONN/A
(303) 222-📞LandlineDENVERMCIMETRO ACCESS TRANSMISSION SERVICES LLCN/A
(303) 223-📞LandlineDENVERLEVEL 3 COMMUNICATIONS, LLC - CON/A
(303) 224-📞LandlineDENVERQWEST CORPORATIONN/A
(303) 225-📞LandlineDENVERLEVEL 3 COMMUNICATIONS, LLC - CON/A
(303) 226-📞LandlineDENVERLEVEL 3 COMMUNICATIONS, LLC - CON/A
(303) 227-📞LandlineDENVERQWEST CORPORATIONN/A
(303) 228-📞LandlineDENVERLEVEL 3 COMMUNICATIONS, LLC - CON/A
(303) 229-📱WirelessDENVERCELLCO PARTNERSHIP DBA VERIZON WIRELESS - CON/A
(303) 230-📞LandlineDENVERSPOK, INC.N/A
(303) 231-📞LandlineDENVERQWEST CORPORATIONN/A
(303) 232-📞LandlineDENVERQWEST CORPORATIONN/A
(303) 233-📞LandlineDENVERQWEST CORPORATIONN/A
(303) 234-📞LandlineDENVERQWEST CORPORATIONN/A
(303) 235-📞LandlineDENVERQWEST CORPORATIONN/A
(303) 236-📞LandlineDENVERQWEST CORPORATIONN/A
(303) 237-📞LandlineDENVERQWEST CORPORATIONN/A
(303) 238-📞LandlineDENVERQWEST CORPORATIONN/A
(303) 239-📞LandlineDENVERQWEST CORPORATIONN/A
(303) 240-📞LandlineDENVERSPOK, INC.N/A
(303) 241-📱WirelessDENVERCELLCO PARTNERSHIP DBA VERIZON WIRELESS - CON/A
(303) 242-📞LandlineDENVERMCIMETRO ACCESS TRANSMISSION SERVICES LLCN/A
(303) 243-📱WirelessDENVERN.E. COLORADO CELLULAR, INC.N/A
(303) 244-📞LandlineDENVERQWEST CORPORATIONN/A
(303) 245-📞LandlineDENVERQWEST CORPORATIONN/A
(303) 246-📱WirelessDENVERT-MOBILE USA, INC.N/A
(303) 247-📞LandlineDENVERQWEST CORPORATIONN/A
(303) 248-📞LandlineDENVERTELEPORT COMMUNICATIONS AMERICA, LLC - CON/A
(303) 249-📱WirelessDENVERNEW CINGULAR WIRELESS PCS, LLCN/A

Frequently Asked Questions about Area Code 303

Where is area code 303 located?

Area code 303 is located in Colorado (United States), serving cities like Denver, Aurora, Lakewood, Thornton, Arvada, Westminster, Centennial, Boulder, Longmont, Castle Rock.

What timezone is area code 303?

Area code 303 operates in the Mountain timezone.

What state is area code 303?

Area code 303 is assigned to the state / telecom territory of Colorado.

Is area code 303 a scam or dangerous?

Area code 303 is an official geographic area code for Colorado. However, beware of robocaller spoofing.

Colorado State Area Codes

View complete directory of telephone area codes assigned to Colorado.

Explore Colorado Directory

Get a 303 Business Phone Number

How to acquire a virtual phone number or business line with area code 303 for local customer trust in Colorado.

Get 303 Business Number
🛡️ Scam & Safety Directory

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Overlay & Nearby Area Codes for Colorado

Explore neighboring telecom prefixes sharing geographical boundaries with area code 303.

720
Mountain
Area Code 720
Denver, Aurora, Lakewood, Thornton, Arvada, Westminster, Centennial, Boulder, Longmont, Castle Rock
983
Mountain
Area Code 983
Denver, Aurora, Lakewood, Thornton, Arvada, Westminster, Centennial, Boulder, Longmont, Castle Rock
719
Mountain
Area Code 719
Colorado Springs, Pueblo, Cañon City, Monument, Alamosa, Trinidad, Woodland Park, Lamar, La Junta, Salida
748
Mountain
Area Code 748
Fort Collins, Greeley, Loveland, Grand Junction, Windsor, Fountain, Evans, Johnstown, Montrose, Firestone
970
Mountain
Area Code 970
Fort Collins, Greeley, Loveland, Grand Junction, Windsor, Fountain, Evans, Johnstown, Montrose, Firestone