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Starting next summer, new Montgomery County phone numbers will begin with the area code 227 instead of the longstanding 301 or 240.

The Maryland Public Service Commission announced Wednesday that 227 has been assigned as the new area code to serve the geographic area that includes Montgomery, Allegany, Charles, Garrett, Prince George’s, St. Mary’s, Washington, Frederick, Howard, Carroll and Anne Arundel counties, according to a press release.

The new area code is being introduced because the remaining supply of telephone numbers beginning with 240 or 301 will be exhausted in the second quarter of 2023, according to the commission.

Residents and businesses won’t have to change their current phone numbers, but new phone numbers will begin with 227 once all 301 and 240 numbers are exhausted.

The commission approved a request to add the 227 area code from the North American Number Plan Administrator (NANPA), the agency that creates the telephone number plan for North America.

This region of Maryland last received a new area code 25 years ago when 240 was introduced, according to the commission.


Heidi Wayman, manager of data management for NANPA, told Bethesda Beat on Thursday that the 227 area code will be introduced on or after June 14, 2023.

The availability of phone numbers is based on the availability of prefixes, Wayman explained. A prefix is the second three digits in a 10-digit phone number. Each prefix has about 10,000 available phone numbers, she said.

Wayman said there are 21 prefixes remaining for the region’s 240 area code and two prefixes remaining for the 301 area code. She did not have specific numbers for Montgomery County.


The commission says that there won’t be any changes for customers dialing existing 301 and 240 numbers, but recommends the following tips:

  • Check devices to make sure area codes are included with stored numbers
  • Save phone numbers to all devices using the full 10-digit number
  • Ensure that all automatic dialers, alarms and other security systems recognize the new area code.

Dan Schere can be reached at