720 Area Code: Denver and the Front Range

The 720 area code is the telephone prefix that shares Colorado's Denver metropolitan area with 303 and 983 — the belt of the Front Range that runs from Boulder south through Denver, Aurora and Lakewood to the suburbs at the foot of the Rocky Mountains. Introduced in 1998, 720 was one of the earliest all-services overlays in the United States, and it helped make Denver one of the first metros where residents dialed all ten digits for every local call.

This guide covers the full picture: exactly which cities 720 serves, the Mountain time zone it sits in, how the 303, 720 and 983 overlay works, why ten-digit dialing is required, and how to activate a 720 virtual number for a business in minutes.

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The 720 area code is a Colorado numbering plan area that covers the Denver-Boulder metropolitan region along the Front Range. Rather than serving its own separate territory, 720 is an overlay: it sits on top of the same geography as the 303 code and the newer 983 code, so all three share one metro. It was introduced in 1998 to add numbers to a fast-growing region, and because it is an overlay, ten-digit dialing is required for every local call.

Dialing Format and Time Zone

• Dialing format: (720) 555-0187
• International: +1 720-555-0187
• Time zone: Mountain Time (MT) — UTC−7 Standard, UTC−6 Daylight Saving (March–November)
• 10-digit dialing required for all local calls

The 720 area code covers the Denver metropolitan area and the surrounding Front Range — the string of cities that sits where the Great Plains meet the Rocky Mountains. Broadly, the region runs from the city of Denver outward to its ring of suburbs and north to Boulder.

Major Cities and Communities

• Denver — the state capital and economic center of the Rocky Mountain region
• Aurora & Centennial — the large eastern and southern suburbs of the metro
• Lakewood, Arvada & Wheat Ridge — the established western suburbs toward the foothills
• Westminster, Thornton & Broomfield — the growing northern suburbs along the I-25 corridor
• Boulder & Longmont — the university and technology cities to the northwest
• Littleton, Englewood & Highlands Ranch — the southern suburbs toward the Palmer Divide

Because 720 is a metro-wide overlay rather than a regional split, its numbers appear across the entire Denver-Boulder area rather than in any single corner of it.

The entire 720 area code sits within the Mountain Time Zone (MT), the same clock as the rest of Colorado, along with Utah, Montana and much of the interior West. Mountain Time runs at UTC−7 during Standard Time and shifts to UTC−6 during Daylight Saving Time, which spans from mid-March through early November.

For businesses, a Mountain-time number bridges the coasts — the working day overlaps both the Pacific and Eastern time zones, making a 720 line convenient for teams that serve customers nationwide from a central location.

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Denver did not gain 720 through a geographic split, but through an overlay — a second code laid over the exact same territory as the original 303 area code. As the metro boomed in the 1990s, demand for numbers outpaced what a single code could supply, and regulators chose an overlay so that no existing customer would have to change their number.

• 1998 — 720 is added as an overlay across the entire 303 service area, and ten-digit dialing begins
• 2022 — a third code, 983, is layered over the same region as numbers continue to run short
• Today — 303, 720 and 983 all share the Denver-Boulder metro as a single overlay complex

Because the three codes share one geography, a 303 line, a 720 line and a 983 line can sit on the same street, so the full area code must always be dialed. For a business, 720 reads as thoroughly local across the whole metro — no less Denver than the original 303.

The 720 region anchors the economy of the entire Rocky Mountain West, and a 720 number connects a business to a market known for both innovation and the outdoors. Few metros pair a booming tech and aerospace base with such immediate access to the mountains.

Aerospace, Tech and Enterprise

The Front Range is a national center for aerospace and technology, with a dense cluster of space, defense, software and telecom employers across the metro and the research campuses of the University of Colorado. Denver International Airport, one of the busiest airports in the world, ties the region to global markets.

The Rockies and the Outdoors

Denver is the gateway to the Rocky Mountains, and the surrounding Front Range is famous for skiing, hiking and a celebrated craft-beer scene. That mix of enterprise and lifestyle has drawn a steady stream of new residents and businesses, keeping demand for local numbers high.

Modern cloud phone providers let a business activate a 720 number in minutes — no Denver office, no hardware, and no long-term contract. Search available 720 numbers, complete a short verification, and route the line to any device anywhere in the world. Because 720 shares the metro with 303 and 983, a 720 line reads as local across the entire Denver-Boulder area.

A 720 number suits anyone who wants to feel local to Denver and the Front Range: startups and tech firms, professional-services practices, retailers and restaurants, contractors, and remote teams serving Denver, Boulder and the suburbs. MeraTalk provides 720 numbers as part of its cloud telephony platform — lines activate in minutes, route to any device, and pair with voicemail, call recording, auto-attendant and CRM integration from one dashboard. To set up a dedicated business phone number, search available numbers at meratalk.com.

In a metro with a strong sense of place, the prefix on a phone number carries real weight. Denver-area customers recognize 720 and 303 alike as their own, and a call from a familiar local code is far more likely to be answered than one from an unknown or out-of-area number.

• Local trust — Front Range customers answer a familiar 720 prefix more readily than distant or unknown numbers
• Metro reach — as a Denver-wide overlay, 720 signals presence across the entire metro, not one suburb
• Local search presence — a number matching the service area reinforces listings and word-of-mouth referrals

Because virtual numbers separate the digits from any physical line, even a business without a Denver office can present that Front Range identity while routing calls to any device.

The trust a local prefix carries also makes it a favorite disguise for fraud. Caller-ID spoofing lets someone anywhere in the world display a 720 prefix, so a resident sees what looks like a local call. The prefix itself proves nothing — genuine and spoofed calls look identical on screen, and because 720 is common on mobile and cloud lines, scammers know it blends in.

• Fake bank or payment alerts — a caller claims a "suspicious transaction" and pressures you to act now
• Threats and urgency — warnings of arrest, deportation or a utility shut-off unless you pay immediately
• Unusual payment demands — requests for gift cards, cryptocurrency or a wire transfer

The reliable defense is to hang up and call back through a number found independently — on a bill, an official site, or a saved contact. Never share codes, card numbers or passwords with an unsolicited caller, and know that federal telemarketing sales rules restrict unsolicited calls and require callers to honor do-not-call requests. For more, see telemarketing sales rules.

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