557 area code — Saint Louis, MO geographic
Area code 557 is a geographic code serving Saint Louis, Missouri in the Central time zone. It has been in service since August 12, 2022. Together with 314 it forms the 314/557 overlay. Because of number portability and VoIP, the area code tells you where the number was issued, not where the caller is right now.
NANPA lists 66 active NXX prefixes in 557, assigned to 15 carriers. 66 of those prefixes are pooled — shared between carriers in thousands-number blocks. The code spans 7 rate centers (billing localities).
Its parent code is 314, which it left in 2022.
Official projections put exhaust for the 314/557 complex at 4Q 2060.
The dialing plan is 10D for home-NPA local calls and 10D across codes.
Use this page to decode where 557 numbers come from — and remember that spoofing means the screen can lie about everything except your own caution.
Largest localities in 557
| Locality (rate center) | Active prefixes | Also served by |
|---|---|---|
| Saint Louis | 30 | 314 |
| Ladue | 13 | 314 |
| Kirkwood | 9 | 314 |
| Creve Coeur | 5 | 314 |
| Mehlville | 4 | 314 |
| Sappington | 4 | 314 |
| Oakville | 1 | 314 |
FAQ
Why do 314 and 557 cover the same place?
They are overlays: when a code runs low on numbers, a new code is added over the same territory instead of splitting it. The 314/557 complex shares one service area, and local calls are dialed with 10 digits.
Will 557 run out of numbers?
NANPA's current forecast projects exhaust in 4Q 2060 — decades of capacity remain.
Why am I getting spam calls from 557 numbers?
Scammers spoof recognizable area codes so calls look local or familiar. A displayed 557 number does not prove the call originated there — see our guide to spotting spoofed calls.
Where is a 557 number from?
557 is assigned to Saint Louis and surrounding areas of Missouri in the Central time zone. The three digits after the area code (the prefix) narrow it down to a rate center.