Where in North America is Area Code 399?

Area code 399 is not currently assigned to any geographic location in North America under the North American Numbering Plan (NANP).

If you’re encountering this code, it might be:

1. A reserved or unassigned code that could be used in the future.
2. Part of an internal numbering system for a specific company or service.
3. A potential misinterpretation of another number or part of an international dialing prefix.