Maryland area codes
Maryland has 6 area codes in service: 227, 240, 301, 410, 443 and 667.
- All 6 share their area with at least one other Maryland code through an overlay. The table shows which.
- Newest: 227, in service since Jun 14, 2023.
- Oldest: 301, in service since 1947.
- A local call within any Maryland code is usually dialed with 10 digits, the predominant pattern NANPA records for each.
- On the 07/30/2026 registry file, no new code is assigned to Maryland and no relief planning has begun for any of its codes.
This is public numbering-plan data from NANPA, reproduced as its registry records it. It is not ours, and an area code says where a number was assigned, not where the person holding it lives.
Source: North American Numbering Plan Administrator (NANPA), NPA Database (CSV file at reports.nanpa.com), registry file date 07/30/2026.
Every Maryland area code in the registry
In numeric order, as the NANPA registry file dated 07/30/2026 lists them. An overlay code serves the same area as the code it was laid over.
| Area code | In service since | Overlaid with | Local calls dialed with |
|---|---|---|---|
| 227 | Jun 14, 2023 | 240, 301 | 10 digits |
| 240 | Jun 1, 1997 | 227, 301 | 10 digits |
| 301 | 1947 | 227, 240 | 10 digits |
| 410 | Oct 6, 1991 | 443, 667 | 10 digits |
| 443 | Jun 1, 1997 | 410, 667 | 10 digits |
| 667 | Mar 24, 2012 | 410, 443 | 10 digits |
Two codes are shown as overlaid only where each code's own registry row lists the other. The registry's rows occasionally disagree, and where they do the pairing is left out rather than guessed. The dialing column is the predominant pattern NANPA records for a local call within the same code.
Calling any of these?
The SAGARIS dialer runs on this dataset: your own number pools, local presence matched to the area you are calling, and a daily cap on every number.