US Area Code Statistics
Comprehensive data on the US telephone numbering system. From 77 area codes assigned in 1947 to today's 372 codes in service, explore how the system has evolved.
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US Area Codes by the Numbers
What the numbers count: 375 area codes of the 50 states + DC are in our database.372 are in service; 3 are assigned by NANPA but not yet in service. Of the 372 in service, 13 overlays have no prefixes assigned yet.140 codes were created as overlays (137 of them in service) and 156 as splits. The Exhaustion Study covers the 372 in-service codes with a utilization reading; the Income & Density Study covers the 233 codes with their own Census data.
Methodology note: The "Assigned in 1947" count (77) refers specifically to area codes whose in-service date falls within 1947, when the numbering plan was launched. The Family Trees page shows 79 "Root Codes": the 77 original codes plus2 codes with no parent that were added later (808 Hawaii, 907 Alaska). Population and density charts use only geographic and split codes (excluding overlays) to avoid counting the same region twice.
Data coverage: Demographic statistics (population, income, education, poverty) are available for 233 geographic and split area codes (out of 235). Population and density charts use these same codes: the scatter plot shows 233 data points, and the density-by-state map covers 233 codes. Overlays show the figures of the area code whose territory they cover (labelled on their page); 11 codes have none. See Sources for details.
Population note: Population figures are derived from county-level Census data mapped to area codes via geographic boundaries. These are approximate — the Census Bureau does not publish population data at the area code level. In overlapping metro areas, the same population may appear under multiple area codes. See Sources & Methodology for details.
The Evolution of US Area Codes
In 1947, AT&T and the Bell System introduced the North American Numbering Plan, assigning 77 original area codes assigned in 1947. Each NPA was assigned a 3-digit code using a formula that made the most populated cities easiest to dial on rotary phones.
The 1990s saw the most new area codes with 108 created, driven by mobile phone and fax demand. The 1990s alone produced 108 codes. Since 2000, overlays (137 total) have largely replaced splits (156 total), preserving existing numbers while adding capacity. Of the 372 area codes with activation dates, 79 were original geographic codes, 156 were created by splitting existing area codes, and 137 were created as geographic overlays. 3 additional codes are assigned but not yet in service.
Key Findings
- Our database covers 375 US area codes (372 in service), up from 77 area codes assigned in 1947.
- 156 codes were created by splits, while 140 were created as overlays.
- On average 67.6% of an in-service area code's assignable prefixes are assigned.
- 92 area codes have no vacant prefix left, and 163 are above 90% utilization; these are the codes most likely to need relief planning.
- Since 2000, most new area codes have been overlays rather than splits, preserving existing numbers while adding capacity.
Relief Planning Status
Area codes currently in or approaching exhaust status.
| Code | State | Relief Planning | Expected Exhaustion |
|---|---|---|---|
| 451 | NC | Yes | — |
| 502 | KY | Yes | — |
| 509 | WA | Yes | — |
| 565 | GA | Yes | — |
| 580 | OK | Yes | — |
| 626 | CA | Yes | — |
| 657 | CA | Yes | — |
| 714 | CA | Yes | — |
| 761 | KY | Yes | — |
| 828 | NC | Yes | — |
| 912 | GA | Yes | — |
| 949 | CA | Yes | — |
| 956 | TX | Yes | — |
13 area codes are listed in NANPA's Relief Planning Report (10 in service, 3 assigned but not yet in service: 451 NC, 565 GA, 761 KY). The codes not yet in service have no utilization reading and do not appear in the Exhaustion Study's rankings.
Assigned, Not Yet in Service
Area codes that NANPA has assigned but that have no in-service date yet. They carry no utilization reading and are not part of the Exhaustion Study. (Overlays that are already in service but have no prefixes assigned yet are listed in the study with 0%.)
3 area codes from the NANPA Area Code Database. These overlays have been assigned but are not yet in service.
What the Data Tells Us
Beyond the raw numbers, here are the patterns and insights our analysis reveals. Each conclusion is backed by verifiable data with methodology and source information.
Overlays have replaced geographic splits
Since 1947, 156 area codes have been created as geographic splits and 140 as overlays. The last geographic split was in the 2000s; since the 2010s, overlays have been the sole method of adding new area codes.
Key Evidence
- Total geographic splits created: 156
- Total overlays created: 140
- Last decade with a geographic split: 2000s
- Overlays created since then: 92, with 0 splits
Utilization varies dramatically by state size
The highest average utilization rates are in small states with few area codes (e.g., Montana at 95.9%), while large states with many codes have lower averages. This reflects the mathematical reality that single-code states have no capacity to absorb demand spikes.
Key Evidence
- Top state by avg utilization: MT (95.9%)
- Bottom state by avg utilization: MS (52.7%)
- States with >90% avg utilization: 5
- Total area codes above 90% utilization: 163
Population density varies enormously across area codes
The population density across area codes spans more than four orders of magnitude (from 1 to 71917 people/sq mi). This extreme variation means a single area code can serve both dense urban cores and vast rural regions — a unique characteristic of the US numbering plan.
Key Evidence
- Minimum density: 1 people/sq mi
- Maximum density: 71917 people/sq mi
- Median density: 171 people/sq mi
- Area codes analyzed: 233
Income and area-code density are weakly correlated
There is a weak positive correlation (r = 0.180) between median household income and population density across area codes. While wealthier areas tend to be denser, the relationship is not strong enough to predict one from the other — other factors like telecom infrastructure and regulatory history play significant roles.
Key Evidence
- Pearson correlation (income vs density): 0.180
- Area codes analyzed: 233
- R-squared: 0.032 (only 3.2% of variance explained)
Area Code Utilization by State
Average utilization of area codes in each state. Higher values indicate closer to exhaustion.
Data as of Oct 27, 2026
Average area code utilization by state. Montana leads with 95.9% average utilization across 1 codes. 11 of 51 states/DC have average utilization above 80%, indicating potential future relief planning needs.
Splits vs Overlays Over Time
How area codes have been created since 1947 — by splitting existing codes or adding overlays.
Data as of Oct 27, 2026
From 1947 to 2026, 296 area codes were created: 156 by splits and 140 as overlays. Since 2000, overlays have dominated, with 122 overlays vs 31 splits.
Largest Area Code Family Trees
The original 1947 area codes that spawned the most descendants through splits and overlays.
Demographic Overview
Population, income, and education statistics across all US area codes.
Data as of Oct 27, 2026
Area Code Density by State
Number of area codes per million people. States with higher density need more codes.
Data as of Oct 27, 2026
Income vs Area Code Density
Relationship between median household income, population density, and area code allocation.
Data as of Oct 27, 2026