Area Code Lookup
What Area Code Is Washington Zone 10?
3 area codes serve Washington Zone 10 · Maryland
Washington Zone 10 is served by area codes 227, 240, 301. It is located in Maryland.
Area Codes Serving Washington Zone 10
Frequently Asked Questions
What area code is Washington Zone 10?
Washington Zone 10 is served by area codes 227, 240, 301. It is located in Maryland.
Why does Washington Zone 10 have multiple area codes?
As demand for phone numbers increased, NANPA added area codes through splits (dividing the region) or overlays (layering a new code over the same geography). Washington Zone 10 now has 3 area codes — 227 and 240 and 301 — covering the same or overlapping areas.
How do I call Washington Zone 10 from outside the US?
To call Washington Zone 10 from abroad, dial +1 followed by the area code and 7-digit local number (e.g. +1-227-XXX-XXXX). The +1 is the country code for all NANPA countries.