Upper Marlboro Maryland Area Codes
3 area codes cover Upper Marlboro: 227, 240 and 301. A number carrying any of them is local to Upper Marlboro.
The codes covering Upper Marlboro
| Area code | Primarily serves | Shares ground with | In service |
|---|---|---|---|
| 227 | Baltimore | 240, 301 | 2023 |
| 240 | Baltimore | 227, 301 | 1997 |
| 301 | Baltimore | 227, 240 | 1947 |
A code in the “shares ground” column is an overlay: it covers the same territory rather than a different part of Upper Marlboro, which is why local calls there are dialled as ten digits.
Scope the codes matched to Upper Marlboro. Source geoinfo-dataset (full_dataset) ZIP→NPA (2018 snapshot) and LocalCallingGuide NPA list (2026-07 NPA list). Updated . Overlay relationships come from the numbering-plan authority; the place match is computed.
Which part of town has which code
We do not publish which of these codes covers which street or neighbourhood in Upper Marlboro, and we would rather say so than guess. Area codes are drawn around telephone rate centres, which follow neither municipal boundaries nor ZIP codes, and the per-ZIP telephone data we hold is a 2018 snapshot too noisy to split a city with. Where these codes overlay one another the question has no answer at all: they cover the same ground by design. Awaiting a current, clean-rights rate-centre boundary source.
ZIP codes for the same city
Postal geography is organised separately from telephone geography, so Upper Marlboro’s 5 ZIP codes do not map onto the codes above. They are listed in full, with the county each falls in, on the postal side of the site.
Upper Marlboro Maryland ZIP codes →
Nearby places with different codes
These are the closest places to Upper Marlboro whose area codes are not the same set. If you are near one of them, a local number may carry a code that is not on the list above.
| City | Distance | Their area codes |
|---|---|---|
| Queen Anne Maryland area codes | 6.7 mi | 410, 443, 667 |
| Bowie Maryland area codes | 9.6 mi | 227, 240, 301, 410, 443, 667 |
| Edgewater Maryland area codes | 14 mi | 227, 240, 301, 410, 443, 667 |
| Chesapeake Beach Maryland area codes | 14 mi | 227, 240, 301, 410, 443, 667 |
| North Beach Maryland area codes | 14 mi | 227, 240, 301, 410, 443, 667 |
| Hyattsville Maryland area codes | 15 mi | 227, 240, 301, 410, 443, 667 |
| Annapolis Maryland area codes | 17 mi | 227, 240, 301, 410, 443, 667 |
| Laurel Maryland area codes | 20 mi | 227, 240, 301, 410, 443, 667 |
Straight-line distance between place reference points, not driving distance.