Quick answer: The 720 area code covers the Denver metropolitan area and Front Range — Denver, Aurora, Boulder, Lakewood, and surrounding suburbs. It sits in the Mountain Time Zone, was added in 1998 as an overlay of 303 (with 983 joining in 2022), and shares the exact same territory, so every local call requires all 10 digits.
A 720 number on caller ID does something a toll-free line never will — it tells the Denver metro you belong there. In a region growing this fast, that local signal is worth real money.
But the 720 is easy to misread. It shares its entire map with two other area codes and reaches far past the city of Denver itself.
This guide lays out where the 720 area code reaches, the cities and counties it serves, how the 303 and 983 overlay works, and how any business can claim a Denver number without setting foot in Colorado.
Where the 720 Area Code Is Located
The 720 sits in the heart of Colorado, covering the Denver metropolitan area and its sprawling suburbs. It does not have its own exclusive territory — it shares the identical map with the older 303 code and the newer 983 code, an arrangement called an overlay.
The footprint runs from the southern Denver suburbs north to Boulder and Longmont. It reaches west to the Rocky Mountain foothills and east across the plains. A 720 number, then, represents the whole Front Range metro — not a single neighborhood.
Cities and Counties the 720 Serves
The Denver metro is Colorado's economic engine, and the 720 reaches most of it:
- Denver County — Denver
- Arapahoe County — Aurora, Centennial, Littleton, Englewood
- Jefferson County — Lakewood, Arvada, Golden, Wheat Ridge
- Adams County — Thornton, Westminster, Commerce City
- Boulder County — Boulder, Longmont
- Douglas County — Castle Rock, Parker
- Broomfield County — Broomfield
Portions of Weld, Elbert, Clear Creek, Gilpin, and Park counties also fall inside the boundary. For a business serving the whole metro, that is one recognizable prefix instead of several.
Time Zone
The entire 720 region runs on Mountain Time — MST (UTC-7) from early November to mid-March, and MDT (UTC-6) the rest of the year. Denver sits two hours behind the East Coast, so a noon call in New York reaches Denver at 10 a.m.
The 303, 720, and 983 Overlay Explained
Here is what trips people up. Three area codes — 303, 720, and 983 — all serve the exact same Denver-area map. An overlay layers new numbers onto a region that is running out, without forcing anyone to renumber.
How the Overlay Grew
The 303 code came first, in 1947, serving all of Colorado. By the 1990s, the Denver boom — pagers, fax lines, second phone lines — drained the number pool. The 720 was introduced on June 1, 1998, as the first overlay. A third code, 983, followed on June 17, 2022, for continued relief.
What the Overlay Means for You
Because three codes share one map, ten-digit dialing is mandatory — you always dial the area code, even locally. A 303, 720, or 983 number all carry the same Denver credibility. None outranks the others.
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Is the 720 Area Code a Scam Code?
No. The 720 is a legitimate Colorado code, regulated and in continuous use since 1998. The question still comes up, so it is worth addressing directly.
Scammers spoof caller ID to fake any number, and a spoofed call can display a local 720 number to seem trustworthy. The code itself is safe — neighbor spoofing is the real issue, and it affects every area code in the country.
Treat unexpected calls demanding money or personal data with caution, no matter how local the number looks, and verify through official channels first. VoIP platforms with STIR/SHAKEN caller authentication flag many spoofed calls before they ever ring through.
How to Get a 720 Area Code Number
You do not need a Denver office to use a Denver number. A virtual number routes calls to any phone, anywhere — that is the core edge of a cloud line over traditional phone service.
The Setup Process
With a provider such as My Country Mobile, getting started is quick:
- Choose "local number" and select Colorado with the 720 code.
- Browse available numbers and pick one that fits your brand.
- Activate it and forward calls to your mobile, desk phone, or team.
Most numbers go live within minutes, with no hardware to buy.
Porting an Existing Number
Already own a 720 number elsewhere? You can keep it. Number porting moves your existing line to a new platform without changing the digits. Leave your old service running until the port completes, so no calls slip through the gap.
Putting a Denver Number to Work
A local number is a tool, not just a label. Businesses use a 720 line as an outbound sales line for the Denver metro, where local caller ID lifts answer rates; as a support number that feels reachable to Aurora and Boulder customers; and as separate tracked numbers per ad campaign to measure which one drives the most calls.
You can be based anywhere and still run a credible Denver operation, with calls forwarding to wherever your team actually works. That lets you test the Front Range market before committing to office space or local hires.
The Bottom Line on the 720 Code
The 720 area code is not a single place — it is access to the entire Denver metro, from downtown to Boulder and Castle Rock. Understanding the 303 and 983 overlay is what lets you use it with confidence.
If your customers are in central Colorado, claim a local number before your next campaign. The trust it builds shows up in your answer rates within days.
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FAQs
What cities does the 720 area code cover?
It covers the Denver metro, including Denver, Aurora, Boulder, Lakewood, Thornton, Arvada, Westminster, Centennial, Longmont, Littleton, Castle Rock, and Parker.
Is 720 the same area as 303?
Yes. The 720 is an overlay of 303 — both serve the identical Denver-area map, along with the 983 overlay added in 2022.
What time zone is the 720 area code in?
The whole 720 region uses Mountain Time, observing MST in winter and MDT during daylight saving.
Do 720 numbers require ten-digit dialing?
Yes. Because 303, 720, and 983 share one region, every call needs the full ten-digit number, even local ones.
Can I get a 720 number if I don't live in Colorado?
Yes. A virtual 720 number works from anywhere and routes calls to any phone or team, with no Colorado address required.
How fast can I activate a 720 number?
With a cloud phone provider, most 720 numbers activate within minutes of sign-up, with no installation needed.
