Maryland 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
Maryland 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, Maryland ranks #18 nationally with roughly 6,263,220 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 Maryland Area Codes
The active area codes serving Maryland are listed below, in numerical order. Where a code is an overlay or a split-off from an earlier code, that relationship is noted.
- 227 — Western and southern Maryland, including the Maryland suburbs of Washington, D.C. (overlay of 301 and 240)
- 240 — Western and southern Maryland, including the Maryland suburbs of Washington, D.C. (overlay of 301)
- 301 — Western and southern Maryland, including the Maryland suburbs of Washington, D.C. (Bethesda, Rockville, Silver Spring, Frederick, Hagerstown, Cumberland)
- 410 — Eastern Maryland, including Baltimore, Annapolis, and the Eastern Shore
- 443 — Eastern Maryland, including Baltimore and the Eastern Shore (overlay of 410)
- 667 — Eastern Maryland, including Baltimore and the Eastern Shore (overlay of 410 and 443)
How Maryland’s Area Codes Grew Over Time
Maryland received its first area code, 301, 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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Browse Maryland Area Codes →- 1947 — 301 assigned as Maryland's sole area code at the launch of the North American Numbering Plan, covering the entire state.
- 1991 — 410 split off from 301 for Baltimore, Annapolis, and the Eastern Shore. It entered service on October 6, 1991, with mandatory ten-digit dialing across the new boundary effective November 1, 1991.
- 1997 — 240 activated on June 1, 1997, as Maryland's first overlay, joining 301 in the western and southern part of the state.
- 1997 — 443 activated on July 1, 1997, as an overlay of 410 in the eastern part of the state.
- 2012 — 667 activated on March 24, 2012, as a second overlay of the 410/443 numbering plan area.
- 2023 — 227 went into service on June 14, 2023, as a third overlay of the 301/240 numbering plan area in western and southern Maryland.
Why Maryland 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.
Maryland’s population of roughly 6,263,220 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.
Maryland Area Codes by Region
Western and southern Maryland (Washington, D.C. suburbs) (301, 240, 227): Maryland's portion of the Washington metro area plus southern and rural western Maryland, including Bethesda, Rockville, Silver Spring, Frederick, Hagerstown, and Cumberland. 301 is the original 1947 code; 240 was added as an overlay in 1997; 227 was added as a second overlay in 2023.
Eastern Maryland (Baltimore and the Eastern Shore) (410, 443, 667): Baltimore, Annapolis, and the Eastern Shore. 410 split off from 301 in 1991; 443 overlay was added in 1997; 667 overlay was added in 2012.
What’s Next for Maryland Area Codes
Maryland’s two numbering plan areas each carry three overlay codes, which has eased near-term pressure on the state’s numbering pool. The eastern 410/443/667 area gained its most recent overlay in 2012, and projections referenced in NANPA’s exhaust analyses suggested a fourth code would not be needed in that region until around 2030. The western 301/240/227 area received its third overlay in June 2023 after the prior codes approached central office code exhaustion, which should provide a multi-year runway. No Maryland numbering plan area appears on NANPA’s near-term relief schedule, with the Baltimore region the more likely first candidate for additional relief later this decade.
Frequently Asked Questions
How many area codes does Maryland have right now?
Maryland 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 Maryland?
301 is the oldest active area code in Maryland, 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 Maryland?
The most recent area code addition to Maryland was 227, activated in 2023. New phone lines provisioned in its service area are increasingly drawn from this code as older overlays approach exhaustion.
Why does Maryland 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 Baltimore?
Baltimore is served by three overlay codes covering the same territory: 410 (the original for eastern Maryland, split from 301 in 1991), 443 (added in 1997), and 667 (added in 2012). New phone lines in the Baltimore area may be assigned any of the three, and ten-digit dialing is required for local calls.
What area code is used for the Maryland suburbs of Washington, D.C.?
The Maryland suburbs of Washington, including Bethesda, Silver Spring, Rockville, and Gaithersburg, fall within the 301 numbering plan area, which is overlaid by 240 and 227. All three codes serve the same region, so a number in Montgomery or Prince George’s County could carry 301, 240, or 227.
Is 227 a real Maryland area code?
Yes. 227 is the newest Maryland area code, going into service on June 14, 2023, as an overlay of the 301/240 region in western and southern Maryland. It was added because the existing 301 and 240 codes were running low on available central office prefixes.
Why does Maryland use ten-digit dialing?
Because every part of Maryland is covered by overlapping overlay codes, the same geographic area can have multiple area codes. To make sure calls reach the right number, callers must dial the full ten-digit number (area code plus the seven-digit number) for local calls; the leading 1 is not required.
Ready to Get a Number in Maryland?
We carry available Maryland numbers right now across multiple area codes. Order directly in 240, 443, 667, 227, or 301 — a one-time fee, no monthly charges, with pricing From $150 depending on the digit pattern and memorability of the number. Prefer help choosing? Call us at (212) 580-2000.
