Frequently Asked Questions
Denver, Colorado uses two area codes: 720 and 303. These area codes are overlaid, meaning they cover the same geographic region. As a result, 10-digit dialing (area code + 7-digit number) is required for all local calls within the Denver metropolitan area.
Denver uses two area codes, 720 and 303, due to the region's rapid population growth. Area code 720 was implemented in 1998 as an overlay to 303 to accommodate the increasing demand for phone numbers. Both area codes serve the same geographic area, necessitating 10-digit dialing for all local calls.
Always dial all 10 digits (area code + 7-digit number) when calling a 720 number, even for local calls within the Denver area. This is because 720 and 303 are overlaid area codes serving the same region. For calls from outside Colorado, dial 1 + the 10-digit number.
Area code 720 covers many cities in the Denver metropolitan area, including Arvada, Denver, Aurora, Lakewood, Boulder, and Centennial. It also includes portions of counties such as Denver, Arapahoe, Jefferson, Adams, and Boulder. Even smaller towns within these counties likely fall under the 720/303 overlay.
Area code 720 covers the north-central region of Colorado, primarily the Denver metropolitan area. It's overlaid on top of the existing 303 area code, meaning both codes serve the same geographic region. This necessitates 10-digit dialing for all local calls within the area.
You should always use 10-digit dialing (area code + 7-digit number) when making local calls within the Denver metropolitan area. This is because Denver uses two overlaid area codes, 720 and 303, covering the same geographic region. 10-digit dialing ensures your calls connect correctly.
Area code 720 is the overlay for area code 303 in Colorado. Both area codes serve the same geographic region, primarily the Denver metropolitan area. This overlay system requires 10-digit dialing for all local calls within the region.
No, you cannot dial just 7 digits within the 720 area code. Because 720 and 303 are overlaid, covering the same area, 10-digit dialing (area code + 7-digit number) is always required for local calls. This ensures successful call completion.
Arvada, Colorado's latitude is 39.80276 and its longitude is -105.08748. These coordinates place Arvada near the center of the Denver metropolitan area, reflecting its central location within the 720 area code.
Area code 720, like all North American area codes, is under the jurisdiction of NANPA (North American Numbering Plan Administration). The Colorado Public Utilities Commission (PUC) also regulates telecommunications services within the state, including those in the 720 area code.
Information on Colorado Public Utilities Commission (PUC) regulations can be found on their official website. The PUC plays a crucial role in regulating telecommunications services within Colorado, including those within the 720 area code.
Area Code 720: Complete Guide to Denver-Area Coverage, Cities, and Dialing
Area code 720 serves the Denver metropolitan area in Colorado. Implemented on June 1, 1998 as an overlay to the original 303 area code, it addresses the growing demand for telephone numbers driven by population growth and the proliferation of mobile phones and pagers. The 720/303 overlay complex now includes a third area code (983, activated June 17, 2022), providing approximately 23.8 million phone numbers for a population of about 3.5 million people in the region. As of 2024, approximately 96.1% of available prefixes have been assigned, with 769 active prefixes serving the area. This guide covers everything you need to know about the 720 area code: geographic coverage, major cities served, dialing patterns, regulatory oversight, telecommunication services, and helpful resources.
Where is Area Code 720 Located?
Area code 720 serves the north-central region of Colorado, overlaying the existing area code 303. Both area codes cover the same geographic area, requiring 10-digit dialing for all calls within the region. This overlay system, implemented in 1998, addressed the increasing demand for phone numbers from the Denver area's rapid population growth. The numbering plan area (NPA) comprises Denver and Boulder, as well as their surrounding suburbs, including Lakewood, Littleton, Longmont, Broomfield, Aurora, and Castle Rock.
What Cities Are in the 720 Area Code?
Area code 720 covers 25 cities and 10 counties across Colorado's Front Range. The most prominent cities include:
Complete County Coverage: Area code 720 covers ten counties: Denver, Jefferson, Arapahoe, Weld, Adams, Boulder, Douglas, Clear Creek, Gilpin, and Larimer. Together, these counties represent a total Census 2020 population of 3,865,062 people.
The 720/303/983 overlay also includes smaller communities such as Littleton, Brighton, Englewood, Golden, Westminster, Wheat Ridge, Erie, Highlands Ranch, Castle Rock, and Columbine, along with mountain communities like Evergreen, Idaho Springs, and Allenspark.
Similar area code overlays exist in other major metropolitan areas, such as area code 201 in New Jersey and area code 202 in Washington DC.
How to Dial Area Code 720: A Practical Guide
The 720/303/983 overlay requires specific dialing patterns to ensure successful call completion. Here's what you need to know:
Standard Dialing Requirements
Local Calls within the Overlay Area:
Long-Distance Calls:
Operator-Assisted Calls: 0 + 10 digits
Emergency and Special Services:
Technical Terms Explained
Common Dialing Scenarios
Scenario 1: Calling from a 720 number to a 303 number in Denver
Scenario 2: Calling from Denver (720) to Colorado Springs (719)
Scenario 3: Calling from outside Colorado to a 720 number
Troubleshooting Call Connection Issues:
If your call doesn't connect:
Equipment Updates Required: Ensure all devices recognize 10-digit dialing and the 983 area code: cordless phones, PBX systems, fax machines, alarm systems, medical alert devices, gate systems, and contact lists.
Geographic Coordinates: Pinpointing Arvada
Arvada's geographic coordinates are:
These coordinates place Arvada near the center of the Denver metropolitan area, reflecting its central role within the 720 area code. Use these coordinates for mapping and location-based services. Other major city coordinates in the 720 area include Denver (39.7392° N, 104.9903° W) and Boulder (40.0150° N, 105.2705° W).
Regulatory Information: Navigating the Telecom Landscape
Area code 720, like all North American area codes, falls under the jurisdiction of the North American Numbering Plan Administration (NANPA). NANPA manages the allocation of area codes and phone number resources. The Colorado Public Utilities Commission (PUC) regulates telecommunications services within the state, including oversight of area code implementations and consumer protection.
Number Portability Rights
Under FCC regulations, you have the right to keep your phone number when changing service providers within the same geographic area:
Key Portability Facts:
How to Port Your Number:
Consumer Protection Resources:
Telecommunications Services: Connecting Colorado
Area code 720 supports a wide range of telecommunications services for residential and business needs. The overlay structure with area codes 303 and 983 ensures sufficient number availability for the region's growing population and expanding businesses, with approximately 23.8 million phone numbers available across the three-code overlay complex.
Service Types Available
Landline Services: Traditional wireline telephone service from carriers including CenturyLink (formerly Qwest) and other local providers. As of 2024, approximately 60.7% of active 720 prefixes support landline use.
Wireless Services: Mobile phone service from major carriers and regional providers. Approximately 39.3% of active prefixes support wireless use, though number portability allows any number to function as wireless.
VoIP (Voice over Internet Protocol) Services: Virtual phone numbers and internet-based calling from providers including:
VoIP Advantages for 720 Numbers:
Carrier Services: Choosing the Right Provider
Major telecommunications carriers serving area code 720 include:
Wireline/Landline Providers:
Wireless Carriers:
Selection Criteria for Choosing a Provider:
Infrastructure Notes:
Additional Resources: Expanding Your Knowledge
For further information on area codes, telecommunications regulations, and related topics, explore these resources:
Federal & State Regulatory:
Local & Economic Development:
Consumer Tools:
For more information on phone number formats and standards, see our guide on E.164 phone number formatting.
Frequently Asked Questions About Area Code 720
What cities are in the 720 area code?
Area code 720 serves major Colorado cities including Denver, Aurora, Arvada, Lakewood, Boulder, Thornton, and Centennial. The 720 area code covers 25 cities total throughout the Denver metropolitan area and overlays with area codes 303 and 983, serving the same geographic region across multiple counties: Denver, Arapahoe, Jefferson, Adams, Boulder, Weld, Douglas, Clear Creek, Gilpin, and Larimer counties.
Is area code 720 the same as 303?
Yes, area code 720 and 303 serve the same geographic area in Colorado. Area code 720 was introduced on June 1, 1998 as an overlay to area code 303 to accommodate the growing demand for phone numbers in the Denver metropolitan area from population growth and mobile device proliferation. A third overlay, 983, was added on June 17, 2022. All three area codes (303, 720, and 983) cover identical territories, requiring 10-digit dialing for all calls within the region.
Do I need to dial 1 before calling a 720 number?
For local calls within the 720/303/983 overlay area, dial all 10 digits (area code + 7-digit number) WITHOUT the "1" prefix. For calls from outside Colorado or when calling other Colorado areas outside the 720/303/983 region (such as Colorado Springs with 719), dial 1 + 10 digits. Always use 10-digit dialing for local calls in the Denver metro area. FCC regulations mandate 10-digit dialing in overlay areas.
When was area code 720 introduced?
Area code 720 was officially implemented on June 1, 1998 as an overlay to the existing area code 303. The implementation process involved a transition period where consumers and businesses updated their dialing habits and equipment to accommodate mandatory 10-digit dialing. This overlay system was designed to address the rapid population growth and increasing demand for phone numbers in the Denver metropolitan area, driven by the proliferation of cell phones, pagers, fax machines, and internet dial-up connections. The Colorado Public Utilities Commission oversaw the implementation with public notification campaigns to educate residents about the change.
Can I get a 720 phone number for my business?
Yes, you can obtain a 720 phone number for your business through various telecommunications carriers operating in the Denver area. Options include:
Traditional Carriers:
VoIP Providers (Popular for Businesses):
Steps to Obtain a 720 Number:
Cost Considerations: Basic business lines range from $20–50/month for traditional service, while VoIP options may range from $15–40/user/month depending on features. Number acquisition may incur one-time setup fees ($0–50 typically).
What is the time zone for area code 720?
Area code 720 operates in the Mountain Time Zone (MT), which is UTC-7 during Mountain Standard Time (MST) and UTC-6 during Mountain Daylight Time (MDT). Colorado observes daylight saving time, with clocks moving forward one hour in March and back one hour in November. This applies to all cities and communities within the 720 area code, including Denver, Aurora, Boulder, and surrounding areas in Colorado.
How do I block spam calls from 720 numbers?
Block spam calls from 720 numbers using these methods:
Built-in Phone Features:
Carrier-Provided Services:
Third-Party Apps:
Government Registry:
Report Scams:
Is area code 720 toll-free?
No, area code 720 is not a toll-free number. It's a standard geographic area code for the Denver metropolitan area in Colorado. Toll-free area codes include 800, 888, 877, 866, 855, 844, and 833. Calls to 720 numbers are charged according to your phone plan's local or long-distance rates. Within the 720/303/983 overlay area, local calls are typically included in unlimited calling plans, but long-distance charges may apply when calling from outside the region depending on your service plan.
What counties does area code 720 cover?
Area code 720 covers ten counties in Colorado: Denver County, Jefferson County, Arapahoe County, Weld County, Adams County, Boulder County, Douglas County, Clear Creek County, Gilpin County, and Larimer County (partial). This includes the Front Range urban corridor and extends throughout the north-central region of Colorado, encompassing both major cities and smaller communities within these county boundaries. The total population served is approximately 3.87 million people according to the 2020 Census.
How can I verify if a 720 number is legitimate?
Verify a 720 number's legitimacy using these methods:
Reverse Lookup Services:
Search Engines:
Red Flags to Watch For:
Verification Steps:
Reporting Suspicious Activity:
What happens if the 720 area code runs out of numbers?
As of 2024, area code 720 (along with overlays 303 and 983) has 23.8 million available phone numbers serving approximately 3.5 million people. Current data shows 96.1% of 720 prefixes are assigned, but the addition of 983 in 2022 relieved immediate exhaustion concerns. If number exhaustion becomes imminent again, NANPA and the Colorado PUC would implement another overlay area code. No further relief planning is currently underway, indicating sufficient number capacity for the foreseeable future.
Summary: Everything You Need to Know About Area Code 720
Area code 720 serves as a critical telecommunications identifier for the Denver metropolitan area in Colorado. This overlay area code, implemented on June 1, 1998, alongside area code 303 (and joined by 983 in 2022), covers major cities including Denver, Aurora, Arvada, Lakewood, Boulder, Thornton, and Centennial across ten counties.
Key Points:
Next Steps to Explore:
Conclusion: Mastering Area Code 720
Area code 720 is a vital component of Colorado's telecommunications network serving the Denver metropolitan area. Understanding its coverage (25 cities across 10 counties), dialing patterns (mandatory 10-digit local dialing), regulatory framework (NANPA and Colorado PUC oversight), and available services (landline, wireless, and VoIP options) helps you navigate the local telecom environment effectively.
The overlay system with 303 and 983 provides sufficient capacity with 23.8 million available numbers for continued regional growth. Whether you're a resident, a business owner, or visiting the area, this guide equips you with the knowledge to communicate seamlessly within the 720 area code. Remember: the 720/303/983 overlay requires 10-digit dialing for all local calls without the "1" prefix – essential for successful communication in the Denver metropolitan area. As the region continues to grow, understanding area code 720 and your consumer rights (including number portability and spam protection) becomes increasingly important for staying connected in Colorado's dynamic Front Range corridor.