image:Area code 301.svg, 300px, alt=area codes 227, 240, and 301. These numbers are related to the main zip codes of Maryland., Maryland consists of the red and blue areas. The red area has area codes 227, 240 and 301. poly 336 37 323 30 310 13 305 -2 337 2

Area codes 215, 267, and 445 Area codes 215, 267, and 445 are telephone area codes in the North American Numbering Plan (NANP) for Philadelphia and adjacent portions of Bucks and Montgomery counties in the U.S. state of Pennsylvania. Area code 215 was one of the original ...

poly 339 121 325 118 296 86 296 73 307 56 319 51 328 48 327 42 337 34

Area code 856 Area code 856 is a telephone area code in the North American Numbering Plan (NANP) for the southwestern part of the U.S. state of New Jersey. The numbering plan area (NPA) includes the Camden, Cherry Hill, and Vineland areas and a small part of ...

poly 248 1 257 11 265 35 253 43 264 50 258 64 278 67 286 56 294 54 305 58 328 47 324 41 335 35 322 30 304 -2 Area code 484 poly 85 65 88 53 101 43 109 48 111 33 100 12 94 4 100 -1 245 -1 258 12 266 35 250 43 263 50 256 66 Area code 717 poly 36 1 43 9 38 19 37 29 17 44 14 67 84 66 87 53 101 44 106 48 111 35 96 5 96 -1 Area code 814 poly 2 2 0 65 16 68 18 43 39 30 40 17 45 10 35 2

Area code 724 Area code 724 is a telephone area code in the North American Numbering Plan for the Commonwealth of Pennsylvania in western and southwestern Pennsylvania, including a portion of the suburbs of Pittsburgh. It was created in an area code split of ...

poly 181 143 184 134 195 144 186 156 184 147 182 142 Area code 202 poly 168 182 169 171 177 170 176 165 184 162 184 152 179 139 168 135 171 131 148 123 141 129 148 166 Area code 571 poly 327 230 290 235 282 236 283 246 317 243

Area codes 757 and 948 Image:Area code 757.png, The area colored red indicates the southeast corner of Virginia served by area code 757 poly 60 2 11 58 12 78 32 106 40 109 45 105 68 123 73 119 95 128 97 122 126 124 132 110 127 103 139 79 154 79 176 42 197 41 217 1 250 ...

poly 336 153 335 186 288 188 277 69 286 56 294 55 303 57 298 76 299 88 316 129

Area code 302 Area is the measure of a region's size on a surface. The area of a plane region or ''plane area'' refers to the area of a shape or planar lamina, while '' surface area'' refers to the area of an open surface or the boundary of a three-di ...

poly 337 190 327 226 278 242 235 193 219 187 214 168 211 157 211 135 205 121 201 116 198 109 200 105 173 94 175 86 167 66 275 67 288 188

Area codes 410, 443, and 667 image:Area code 410.svg, alt=area codes 227, 240, and 301. These numbers are related to the main zip codes of Maryland., Maryland's area codes highlighted in red and blue poly 336 37 323 30 310 13 305 -2 337 2 Area codes 215, 267, and 445 poly 3 ...

poly 0 68 -1 184 16 191 22 186 38 151 51 159 85 118 88 103 87 90 125 121 133 106 135 97 129 92 128 87 122 84 126 81 126 75 116 77 104 68 98 69 93 75 86 73 81 77 79 84 69 84 61 81 59 76 59 73 54 74 43 93 37 88 32 87 31 94 4 117 5 67 Area code 304/681 poly 247 250 249 239 221 220 214 212 200 213 189 199 184 211 169 211 142 226 121 223 106 243 113 248

Area code 804 Image:Area code 804.png, The area colored red indicates the geographical region of Virginia served by area code 804 poly 64 0 54 9 40 24 28 57 13 58 12 77 31 106 40 109 48 106 68 123 75 117 96 127 99 121 126 122 134 110 126 103 137 78 156 78 177 ...

poly 48 250 34 235 60 212 84 208 79 192 77 189 93 172 106 185 122 223 106 243 107 247

Area code 434 Image:Area code 434.png, The area colored red indicates the geographical region of Virginia served by area code 434 poly 64 0 54 9 40 24 28 57 13 58 12 77 31 106 40 109 48 106 68 123 75 117 96 127 99 121 126 122 134 110 126 103 137 78 156 78 17 ...

# poly 1 248 1 184 15 193 22 187 39 151 49 159 58 142 62 147 67 137 69 140 84 118 88 102 87 90 126 123 135 105 138 107 144 105 149 110 153 112 154 114 147 120 149 123 142 131 148 168 167 182 164 189 169 199 179 199 185 193 189 198 183 211 168 211 143 227 121 224 106 184 94 172 78 189 85 208 61 211 34 237 44 247 Area code 540 # desc bottom-left Area codes 301, 240, and 227 are

telephone A telephone, colloquially referred to as a phone, is a telecommunications device that enables two or more users to conduct a conversation when they are too far apart to be easily heard directly. A telephone converts sound, typically and most ...

area code A telephone numbering plan is a type of numbering scheme used in telecommunication to assign telephone numbers to subscriber telephones or other telephony endpoints. Telephone numbers are the addresses of participants in a telephone network, rea ...

s in the

North American Numbering Plan The North American Numbering Plan (NANP) is an integrated telephone numbering plan for twenty-five regions in twenty countries, primarily in North America and the Caribbean. This group is historically known as World Zone 1, World Numbering Zone ...

(NANP) for the western part of the

U.S. state In the United States, a state is a constituent political entity, of which there are 50. Bound together in a political union, each state holds governmental jurisdiction over a separate and defined geographic territory where it shares its so ...

Maryland Maryland ( ) is a U.S. state, state in the Mid-Atlantic (United States), Mid-Atlantic region of the United States. It borders the states of Virginia to its south, West Virginia to its west, Pennsylvania to its north, and Delaware to its east ...

. The numbering plan area (NPA) comprises Maryland's portion of the Greater

Washington, D.C. Washington, D.C., formally the District of Columbia and commonly known as Washington or D.C., is the capital city and federal district of the United States. The city is on the Potomac River, across from Virginia, and shares land borders with ...

metro area, portions of southern Maryland, along with rural

western Maryland upright=1.2, An enlargeable map of Maryland's 23 counties and one independent city Western Maryland, also known as the Maryland panhandle or Mountain Maryland, is the portion of the U.S. state of Maryland that typically consists of Washing ...

. This includes the communities of

Cumberland Cumberland ( ) is an area of North West England which was historically a county. The county was bordered by Northumberland to the north-east, County Durham to the east, Westmorland to the south-east, Lancashire to the south, and the Scottish ...

, Frederick, Hagerstown,

Gaithersburg Gaithersburg ( ) is a city in Montgomery County, Maryland, United States. At the time of the 2020 United States census, Gaithersburg had a population of 69,657, making it the third-largest incorporated city and the ninth-most populous communit ...

, Potomac, Germantown, Bethesda, Rockville, Landover, Silver Spring, and Waldorf. Area code 301 was the first area code for all of Maryland, from 1947, when the area code system was created, until 1991, when everything from

Baltimore Baltimore is the most populous city in the U.S. state of Maryland. With a population of 585,708 at the 2020 census and estimated at 568,271 in 2024, it is the 30th-most populous U.S. city. The Baltimore metropolitan area is the 20th-large ...

eastward was split off as area code 410. In 1997, area code 240 was added as an overlay area code for the 301 territory. On June 14, 2023, a third overlay code, 227, was added to provide more central office prefixes for new telephone numbers.

History

Area code 301 was one of the

original North American area codes The original North American area codes were established by the American Telephone and Telegraph Company (AT&T) in 1947. The assignment was in accord with the design of a uniform nationwide telephone numbering plan that supported the goal of dialin ...

when the

American Telephone and Telegraph Company AT&T Corporation, an abbreviation for its former name, the American Telephone and Telegraph Company, was an American telecommunications company that provided voice, video, data, and Internet telecommunications and professional services to busi ...

(AT&T) established a new, nationwide

telephone numbering plan A telephone numbering plan is a type of numbering scheme used in telecommunication to assign telephone numbers to subscriber telephones or other telephony endpoints. Telephone numbers are the addresses of participants in a telephone network, reach ...

in 1947. The area code served the entire state of Maryland. Much of the

Washington metropolitan area The Washington metropolitan area, also referred to as the National Capital Region, Greater Washington, or locally as the DMV (short for Washington, D.C., District of Columbia, Maryland, and Virginia), is the metropolitan area comprising Washing ...

is part of a local calling area which is centered on the District's area code 202, and also extends into the suburban area in southern Maryland with 301 and

Northern Virginia Northern Virginia, locally referred to as NOVA or NoVA, comprises several County (United States), counties and independent city (United States), independent cities in the Commonwealth (U.S. state), Commonwealth of Virginia in the United States. ...

with area code 703. From 1947 to 1990, it was possible to dial any other telephone number in the metro area as a local call with only seven digits, not using an area code, irrespective of the home area code. The entire metro area was also reachable via long-distance services by dialing area code 202, for which purpose AT&T had established cross-referenced operator routing codes for all affected central offices. This was implemented via a system of central office code protection, meaning that no central office code in the metro area could exist in more than a single central office. For example, if 202-574 numbers were in use in the District or 703-574 numbers were in use in Northern Virginia, the corresponding 301-574 numbering block could only be assigned in areas considered a safe distance away from the capital, such as the

Eastern Shore of Maryland The Eastern Shore of Maryland is a part of the U.S. state of Maryland that lies mostly on the east side of the Chesapeake Bay. Nine counties are normally included in the region. The Eastern Shore is part of the larger Delmarva Peninsula that Ma ...

Ten-digit dialing

By the end of the 1980s, the Washington metropolitan area was running out of assignable prefixes for new central offices on both sides of the

Potomac River The Potomac River () is in the Mid-Atlantic (United States), Mid-Atlantic region of the United States and flows from the Potomac Highlands in West Virginia to Chesapeake Bay in Maryland. It is long,U.S. Geological Survey. National Hydrography D ...

. The only unassigned prefixes were unavailable due to the central office code protection that maintained seven-digit dialing in the metro-area. Assignment of these prefixes would require dialing an area code. The three local operating companies of the

Chesapeake and Potomac Telephone Company The Chesapeake and Potomac Telephone Company, usually known as C&P Telephone, is a former d/b/a name for four Bell Operating Companies providing service to Washington, D.C., Maryland, West Virginia, and Virginia. Today, three of the companies ...

(C&P Telephone, later part of Bell Atlantic and now

Verizon Verizon Communications Inc. ( ), is an American telecommunications company headquartered in New York City. It is the world's second-largest telecommunications company by revenue and its mobile network is the largest wireless carrier in the ...

) cooperated in ending code protection for the Washington area on October 1, 1990. Ten-digit dialing was now required for all local calls between Maryland, the District of Columbia, and Virginia. Area code 202 was no longer usable for suburban points. Local calls within Maryland did not require the area code.Jordan, Mary; Quimpo, Margie G. (September 23, 1990). "Territorial Telephones; On Oct. 1, Local Calls Will Get Complicated". ''The Washington Post''. p. 1. Permissive dialing using the old dialing procedures continued from April 1 through October 1, 1990.

410-split

Due to the overall growth of the Baltimore–Washington metropolitan area, it became apparent by the end of the 1980s that terminating central office code protection in the Washington area could not free up sufficient resources north of the

to stave off the immediate need for a new area code. In mitigation action,

and the Eastern Shore were reassigned from area code 301 to area code 410 on November 1, 1991, to form a new numbering plan area. The

area code split In telecommunications, an area code split is the practice of introducing a new telephone area code by geographically dividing an existing numbering plan area (NPA), and assigning area codes to the resulting divisions, but retaining the existing a ...

largely followed metropolitan area lines with a few exceptions. While Howard County is often recognized as part of the Baltimore metropolitan area, a small portion of the county remained in 301, while the rest of the county was reassigned to 410. When an area code is split, the largest city in the old numbering plan area (in this case Baltimore) typically retains the existing area code to minimize expense for changing telephone numbers. However, Bell Atlantic opted to leave the western half of the state in 301 so as to spare the large number of federal agencies on the Maryland side of the Washington area from the expense and disruption of a new area code. While Maryland would have likely needed another area code due to the growth of the Baltimore-Washington corridor, it is likely that a split would have been delayed had more 301 numbers been available for use in Baltimore.

240-overlay

Although the area code split was intended as a long-term solution, within four years 301 was close to exhaustion due to the proliferation of cell phones and pagers, especially in the Washington suburbs. In relief action, area code 240 was introduced on June 1, 1997, to form the state's first overlay. Overlays were a new concept at the time, and met with some resistance due to the requirement for

ten-digit dialing Ten-digit dialing is a telephone dialing procedure in the countries and territories of the North American Numbering Plan (NANP). It is the practice of including the area code of a telephone number when Dialling (telephony), dialing to initiate a t ...

. It was decided to create an overlay rather than split the region into two numbering plan areas to avoid assigning a new area code to 1.2million existing telephone numbers. At the time, it was predicted that it would take until 2008 to exhaust area code 240.

227-overlay

A September 2022 study projected that the 301/240 numbering plan area (NPA) would suffer central office code exhausted between April and June 2023. Area code 227 was already approved as an all-services distributed overlay since January 3, 2001 for the 301/240 NPA.Duffy, Ken (September 28, 2022).
New Area Code Coming to Parts of Maryland
. '' WBAL''. The new area code went into service on June 14, 2023, at which time activation of new central office codes could begin, once all assignable central office codes in 240/301 had been exhausted.

Service area

The numbering plan area 301/240/227 includes all of Allegany,

Charles Charles is a masculine given name predominantly found in English language, English and French language, French speaking countries. It is from the French form ''Charles'' of the Proto-Germanic, Proto-Germanic name (in runic alphabet) or ''* ...

, Garrett, Montgomery, Prince George's, St. Mary's and Washington counties, most of Frederick County, western Howard County, and slivers of southwestern Carroll County and western

Anne Arundel County Anne Arundel County (; ), also notated as AA or A.A. County, is located in the U.S. state of Maryland. As of the 2020 United States census, its population was 588,261, an increase of just under 10% since 2010. Its county seat is Annapolis, wh ...

. Local calls require ten-digit dialing (area code + number, leading "1" is not required). Some areas, such as Rockville,

, Upper Marlboro, Bethesda and Landover in MarylandLocal calling guide: Washington Zone 4, MD
/ref> remain a local call to the District and Northern Virginia.

Notes

References

External links

301 Area Code in Maryland240 Area Code in Maryland
{{DEFAULTSORT:Area codes 227 240 301 227 240 301 301 Telecommunications-related introductions in 1947 Telecommunications-related introductions in 1997 Telecommunications-related introductions in 2023