Colorado has 6 active area codes as of 2026, covering the state through a mix of original 1947 assignments, geographic splits, and modern overlays. This guide walks through the full list, which regions each code serves, the order they came online, and where new codes are most likely to land next.
The Short Answer
Colorado currently has 6 active area codes in service. The count reflects a combination of population growth, the rise of mobile lines, and the way modern numbering allocates blocks — every line activated, whether a cellphone, a business desk line, a VoIP number, or a connected device, consumes a slot in the pool.
By population, Colorado ranks #21 nationally with roughly 5,957,493 residents as of the most recent estimates. That puts the state’s area code count in line with its population peers — denser, faster-growing states need more codes; smaller states need fewer.
The Full List of Colorado Area Codes
The active area codes serving Colorado are listed below, in numerical order. Where a code is an overlay or a split-off from an earlier code, that relationship is noted.
- 303 — Denver-Boulder metro and the north-central Front Range
- 719 — Southeastern, east-central, and south-central Colorado (Colorado Springs, Pueblo)
- 720 — Denver-Boulder metro (overlay of 303)
- 970 — Northern and western Colorado (Fort Collins, Grand Junction, Vail, Aspen)
- 983 — Denver-Boulder metro (overlay of 303 and 720)
- 748 — Northern and western Colorado (overlay of 970)
How Colorado’s Area Codes Grew Over Time
Colorado received its first area code, 303, when the North American Numbering Plan launched in 1947. That single code initially covered the entire state, and subsequent splits and overlays narrowed it over the decades that followed.
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- 1988 — 719 split off from 303 on March 5, 1988, for southeastern, east-central, and south-central Colorado, including Colorado Springs and Pueblo.
- 1995 — 970 split off from 303 on April 2, 1995, for the northern and western parts of the state, including Fort Collins, Grand Junction, Vail, and Aspen. The split reduced 303 to the Denver-Boulder area.
- 1998 — 720 activated on September 1, 1998, as Colorado's first overlay, joining 303 in the Denver-Boulder service area and bringing ten-digit dialing to the region.
- 2022 — 983 activated on June 17, 2022, as a second overlay of the 303/720 complex in the Denver-Boulder metro.
- 2025 — 748 activated on July 7, 2025, as an overlay of 970 in northern and western Colorado. No 748 numbers may be assigned until 970 reaches exhaustion.
Why Colorado Has Multiple Area Codes
A single area code can hold roughly 7.9 million possible phone numbers in theory — 792 valid central office codes (the second three digits) multiplied by 10,000 line numbers each. In practice the usable count is lower, because blocks of numbers are reserved, withheld, or assigned in bulk to carriers that may never fully use them. When the pool of available numbers in an area code falls below the threshold the North American Numbering Plan Administrator (NANPA) tracks, the state requests relief, and either a split or an overlay is approved.
Colorado’s population of roughly 5,957,493 residents would, on its own, fit comfortably inside a single area code’s capacity. The reason 6 codes are needed instead is that every adult typically carries at least one mobile line, many households have multiple lines per person, businesses concentrate phone numbers at extreme density, and connected devices, VoIP services, and second-line apps all draw from the same pool. The math compounds quickly.
Colorado Area Codes by Region
Denver-Boulder metro (303, 720, 983): Denver, Boulder, and surrounding suburbs including Aurora, Lakewood, Littleton, Longmont, Broomfield, and Castle Rock. 303 is the original from 1947; 720 was added as an overlay in 1998; 983 was added as a second overlay in 2022.
Southern Colorado (719): Colorado Springs, Pueblo, the San Luis Valley, and southeastern Colorado. Split off from 303 in 1988.
Northern and western Colorado (970, 748): Fort Collins, Greeley, Loveland, Grand Junction, and the western mountain resort towns such as Vail, Aspen, Breckenridge, and Steamboat Springs. 970 split off from 303 in 1995; 748 overlay added in 2025.
What’s Next for Colorado Area Codes
Colorado’s two relief actions this decade have eased pressure on its busiest pools. The 983 overlay added to the Denver-Boulder complex in 2022 followed a NANPA projection that the metro would otherwise exhaust by 2023, and the 748 overlay activated in 2025 addressed a 2023 NANPA estimate that 970 would reach exhaustion by 2026. With both metro and mountain pools now backed by fresh overlays, no Colorado numbering plan area is on the near-term relief schedule, though continued Front Range growth makes the Denver-Boulder 303/720/983 complex the most likely candidate for future action.
Frequently Asked Questions
How many area codes does Colorado have right now?
Colorado has 6 active area codes in service across the territory it covers, including any overlays that share geography with an older code.
What is the oldest area code in Colorado?
303 is the oldest active area code in Colorado, assigned in 1947 when the North American Numbering Plan launched. It remains in service today, though its geographic footprint has typically been reduced by subsequent splits and overlays.
What is the newest area code in Colorado?
The most recent area code addition to Colorado was 748, activated in 2025. New phone lines provisioned in its service area are increasingly drawn from this code as older overlays approach exhaustion.
Why does Colorado need so many area codes?
Population growth combined with the proliferation of mobile lines, business direct-dial numbers, VoIP services, and connected devices has exhausted older codes faster than the original 1947 plan anticipated. Each new area code adds roughly 7.9 million additional phone numbers to the regional pool.
Which area codes cover Denver?
Three area codes serve Denver and Boulder as an overlay complex: 303 (the original, dating to 1947), 720 (added 1998), and 983 (added 2022). All three cover the same geography, so ten-digit dialing is required and new lines may be assigned any of the three.
What area code is Colorado Springs?
Colorado Springs uses 719, which split off from 303 in 1988. The 719 area also covers Pueblo, the San Luis Valley, Cañon City, Trinidad, and the rest of southeastern and south-central Colorado.
Is 748 a real Colorado area code?
Yes. 748 is an overlay of 970 covering northern and western Colorado, activated on July 7, 2025. Because it shares the same region as 970, no 748 numbers are assigned until the 970 pool runs out, so most lines in that area still carry a 970 number for now.
Why does the Denver area have three area codes?
The Front Range holds most of Colorado’s phone lines, and sustained population growth around Denver and Boulder exhausted the supply of numbers in 303 alone. Rather than splitting the region again, regulators added 720 in 1998 and 983 in 2022 as overlays, layering new codes over the same area instead of redrawing boundaries.
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