Area Code 227
Maryland
Area code 227 serves Maryland, primarily Columbia, in the Eastern Time (ET) time zone. It is an overlay area code sharing territory with area code 301.
Overlay Area Code
This area code is part of an overlay region, meaning the same geographic area is served by multiple area codes. Overlay codes were introduced to meet growing demand for phone numbers without requiring existing customers to change their numbers.
This area code shares its geographic region with: area code 301 (Columbia).
In service since: 14-Jun-2023
Demographics & Economics
- Total Population
- 4,332,726
- Population Density
- 610 people/sq miabove U.S. average (U.S.: 93 people/sq mi)
- Median Household Income
- $90,904above U.S. median (U.S.: $75,144)
- Poverty Rate
- 10.9%near U.S. average (U.S.: 11.5%)
- Unemployment Rate
- 4.9%above U.S. average (U.S.: 3.6%)
- Education Attainment
- Bachelor's Degree+40.5%above U.S. average (U.S.: 33.7%)High School or Lower28.4%
Statistics are population-weighted aggregations from Census ACS 5-year estimates. Population figures are approximate — see Sources & Methodology for details on how area code populations are derived.
See how this area code compares to all US area codes in the Statistics dashboard.
Time Zone
- Eastern Time (ET)
NANPA Relief Status
According to the latest NANPA analysis (July 2026), this area code is not currently listed as exhausting within the next 36 months. No relief planning is in progress for this NPA.
Source: NANPA NPA Relief Planning Reports · See all relief planning statuses
Current Time
Prefix Utilization
Geographic Coverage
State
MD
Major Cities
- Columbia
- Germantown
- Waldorf
- Silver Spring
- Frederick
- Gaithersburg
- Bethesda
- Rockville
- Bowie
- Aspen Hill
- Wheaton
- North Bethesda
- Potomac
- Hagerstown
- Clinton
- Olney
- Chillum
- College Park
- Crofton
- Laurel
- Clarksburg
- South Laurel
- Fairland
- Ballenger Creek
and 299 more cities
Historical Timeline of Area Code 227
Area code 227 was approved by the Maryland PSC on January 3, 2001, in Case No. 8853, but did not go into service until June 14, 2023. The 22-year gap between authorization and activation is among the longest in North American numbering plan history. Area code 227 serves as the third overlay code for western Maryland and D.C. suburbs, joining 301 and 240. (Maryland PSC)
Key milestones:
- 1947: Area code 301 created as one of the original 86 North American area codes, serving all of Maryland. (Wikipedia)
- 1991: Area code 410 split off, taking Baltimore and the Eastern Shore. 301 retained western Maryland and the D.C. suburbs.
- 1997: Area code 240 added as an overlay to 301 territory (June 1, 1997). Maryland's first overlay. Mandatory 10-digit dialing began. (Wikipedia)
- 2001: Maryland PSC Case No. 8853 approved an all-services distributed overlay as the relief method for the 240/301 NPA (January 3, 2001). This pre-authorized a future third overlay code. (Maryland PSC)
- 2022: Maryland PSC voted August 3, 2022 to approve NANPA's petition for the 227 overlay. NANPA issued Planning Letter PL-603 on September 27, 2022. Public announcement followed September 28, 2022. (NANPA)
- 2023: Area code 227 went into service June 14, 2023 as the third overlay for the 301/240 territory. Prefixes became available only after all assignable codes in 240 and 301 were exhausted. (Maryland PSC)
Regulatory History
Area code 227's regulatory history spans over two decades, from the original overlay authorization in 2001 to the final activation in 2023. The key regulatory artifacts are Maryland PSC Case No. 8853 and NANPA Planning Letter PL-603. (NANPA Planning Letters)
| Year | Event | Docket | Regulatory Action & Impact |
|---|---|---|---|
| 2001 | Overlay Authorization | Case No. 8853 | Maryland PSC approved an all-services distributed overlay as the relief method for the 240/301 NPA, pre-authorizing a future third overlay code. (Maryland PSC) |
| 2022 | NANPA Petition Approval | PSC Vote (Aug 3) | Maryland PSC voted to approve NANPA's petition to introduce 227 as the third overlay for the 301/240 territory. (Maryland PSC) |
| 2022 | Planning Letter Issued | PL-603 | NANPA published PL-603 documenting the 227 overlay implementation plan, including network preparation (September 14, 2022), CO code ordering (April 9, 2023), and the June 14, 2023 in-service date. (NANPA) |
| 2022 | Public Announcement | Press Release | Maryland PSC announced the 227 assignment. Estimated number exhaustion Q2 2023. No dialing changes required. (Maryland PSC) |
| 2023 | In-Service Activation | Press Release | Area code 227 went into service June 14, 2023. The 240/301/227 complex serves 11 counties across western Maryland and the D.C. suburbs. (Maryland PSC) |
County Coverage
Population-weighted county share based on aggregated ZCTA population (100% = total mapped population for area code 227).
| County | Population | Share |
|---|---|---|
| Montgomery, MD | 1,168,712 | 34.4% |
| Prince George's, MD | 1,082,938 | 31.9% |
| Frederick, MD | 336,420 | 9.9% |
| Charles, MD | 220,971 | 6.5% |
| Washington, MD | 173,549 | 5.1% |
| Howard, MD | 127,684 | 3.8% |
| St. Mary's, MD | 118,020 | 3.5% |
| Allegany, MD | 69,925 | 2.1% |
| Garrett, MD | 46,232 | 1.4% |
| Carroll, MD | 35,637 | 1.0% |
| Anne Arundel, MD | 7,512 | 0.2% |
| Calvert, MD | 7,512 | 0.2% |
Area Code 227 Family Tree
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Area code 227 was originally assigned in 14-Jun-2023 to serve MD.
Call Context
This area code covers a metropolitan region in MD with moderate to high population density, centered on Columbia and surrounding communities.
Nearby Area Codes
Area codes geographically closest to 227.
Other Area Codes in Maryland
Area codes that also serve Maryland, linked for easy comparison.