Area codes 631 and 934 are the telephone area codes for Suffolk County, New York, comprising the geographic majority of Long Island. It spans from as far west as the Nassau County, New York and Suffolk County, New York border and as far east as Montauk, New York. Area code 631 was created in 1999 as a split-off from area code 516, and 934 was added as an overlay in 2016. Communities within the plan area include Babylon, Huntington, Islip, Smithtown, Brookhaven, Riverhead, Southampton, Southold, Shelter Island, and East Hampton.
History of Suffolk County area codes
On November 1, 1999, area code 631 was created solely for Suffolk County, to satisfy the increased need for telephone numbers mainly due to cellular services, while Nassau County retained area code 516. Permissive dialing for numbers in 516 across Long Island continued until the spring of 2000.
2016–present: 934 overlay
On July 16, 2016, area code 934 was created to overlay 631, which was nearing depletion. This was the first overlay area code for an area in the state of New York outside New York City and required 10-digit dialing for both area codes, effective June 18, 2016.
- "NANP Area Code History: 1948–1959". Area Code History. Archived from the original on September 11, 2002. Retrieved November 4, 2018.
- Rather, John (October 31, 1999). "Suffolk County Gears Up for 631 Area Code". The New York Times. Retrieved November 4, 2018.
- Kitchen, Patricia. "Area code countdown: Suffolk 10-digit dialing begins in June". Newsday. May 14, 2016.
|North: 203, 401, 860, 959|
|West: 516||area code 631/934||East: Atlantic Ocean|
|South: Atlantic Ocean|
|Connecticut area codes: 203/475, 860/959|
|Rhode Island area codes: 401|