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 Codes
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 240 (Columbia), area code 301 (Columbia).
In service since: 14-Jun-2023
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)
Unique Facts About Area Code 227
Area code 227 has several distinctive characteristics. It was approved by the Maryland PSC in 2001 but did not activate until 2023, creating one of the longest gaps between NANP authorization and service dates. (Maryland PSC)
- 22-year approval-to-activation gap: Maryland PSC Case No. 8853 approved the overlay method on January 3, 2001. Area code 227 did not enter service until June 14, 2023. This 22-year span between authorization and activation is among the longest in North American numbering plan history. (Maryland PSC)
- Conditional release mechanism: 227 prefixes were held in reserve and only became assignable after all prefixes in 240 and 301 were exhausted. This conditional deployment ensured the overlay was used only when genuinely needed. (NANPA)
- No dialing changes required: Because 10-digit dialing had been mandatory in the region since the 1997 240 overlay, the introduction of 227 required no changes to existing dialing patterns. (Maryland PSC)
- Third overlay code for western Maryland: Area code 227 became the third code serving the 301/240 territory, joining 301 (1947) and 240 (1997). The combined NPA complex covers 11 counties and serves over 3.3 million residents. (Maryland PSC)
- Forward-looking regulatory decision: In 2001, the Maryland PSC preemptively approved the overlay method for future number relief. This avoided emergency action when exhaustion arrived 22 years later. (Maryland PSC)
FCC 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% |
Call Context
This area code serves the same geographic region as area code 301 in Maryland. It was introduced as an overlay of area code 301, meaning both codes serve the same geographic territory.
Nearby Area Codes
Area codes geographically closest to 227.
Other Area Codes in Maryland
Area codes that also serve Maryland, linked for easy comparison.
Frequently Asked Questions
Common questions about area code 227 and how phone numbering works.
Phone numbers are assigned based on where the number was originally provisioned, not the caller's current location. Mobile phones retain their number when users move, and businesses may use numbers from regions where they don't have a physical presence. VoIP services can also provision numbers from virtually any area code.
Yes, mobile phones can have numbers from any area code in the region they were activated. Wireless carriers assign numbers from available pools regardless of phone type. When users change carriers or move to new areas, they typically keep their original number, which may have a different area code than their current location.
Start by looking up the area code on this site to understand its general geographic region. For the specific number, options include using your carrier's caller ID features or checking public directories. If you suspect fraud, you can report it to the FTC. To file a complaint about robocalls or spoofed numbers, visit the FCC Consumer Complaint Center. You can also register your number with the National Do Not Call Registry to reduce unwanted calls. Keep in mind that caller ID can display any name the caller chooses to set.
When an area's pool of available phone numbers runs low, regulators may introduce an "overlay" area code that covers the same geographic territory as the original. Both codes coexist, and new numbers are assigned from whichever code has availability. This area code shares its region with area code 301, area code 240, area code 301. Learn more in our overlay vs split guide.
While Oakland is a prominent city in this area code's coverage, the code serves the broader surrounding region as well. Area codes are assigned geographically and typically cover multiple cities, towns, and communities beyond any single anchor city.
New area codes are introduced when existing codes in a region approach exhaustion of available number combinations. The telecommunications industry and regulatory bodies plan these additions years in advance to ensure seamless transitions. Recent codes are typically overlays, sharing territory with established codes.