About Area Code 363
- Region Code
- 363
- City
- Nassau County
- State
- New York
- Population
- 1,395,774
- Largest City
- Hempstead
- Time Zone
- Eastern Time
New York
(363) Area Code 363 — Nassau County, New York
363 Area Code – Nassau County, New York: Location, Time Zone & History
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Map of Area Code 363
Available Phone Numbers
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History & Cultural Notes
Nassau County, Long Island, ran out of room in its original numbering plan by the early 2020s, prompting NANPA to announce a new overlay code for the territory in 2022. Area code 363 went into service on January 20, 2023, layered directly over the existing 516 code rather than replacing it, and the change brought mandatory ten-digit local dialing to every number in the region.
With a 2020 U.S. Census population of 1,395,774 across Nassau County, the area supports a diversified economy anchored in healthcare, finance and insurance, retail trade, and education, along with a historic aerospace and defense legacy tied to the former Grumman Corporation. The county is also home to Levittown, one of the first mass-produced suburban housing developments in the United States, built after World War II and widely cited as a model for postwar American suburbia.
Communities sharing the 363/516 numbering plan include Long Beach, Freeport, Garden City, Mineola, and Glen Cove, with Hempstead as the largest served city; the territory borders the 718 and 631 area codes covering the rest of Long Island and New York City.