573
Area code
MO
United States geographic area code, in service since 1996-01-07. Part of the 235/573 overlay complex — ten-digit dialing required.
Statusin service
Introduced1996-01-07
JurisdictionMO, US
Local dialing10D
Time zoneCentral
Last verified2026-09-17
Utilization 101% of assignable prefixes assigned
As of 09/17/2026
0%800 of ~792 assignable NXX values (200–999 excl. N11)100%
Prefix-level assignment does not equal number-level exhaustion; thousands-block pooling extends capacity. First assignment on record 2001-01-10, most recent 2025-09-05.
Area codes serve rate-center geographies, not municipal boundaries. “MO” identifies the jurisdiction, not an exact city footprint.
Top assignees
Ranked by assigned prefixes · initial assignee ≠ current carrier| Rank | Assignee | Prefixes | Share |
|---|---|---|---|
| 01 | SOUTHWESTERN BELL | 128 | 16% |
| 02 | NEW CINGULAR WIRELESS PCS, LLC - IL | 113 | 14.1% |
| 03 | ONVOY, LLC - MO | 86 | 10.8% |
| 04 | LEVEL 3 COMMUNICATIONS, LLC - MO | 63 | 7.9% |
| 05 | T-MOBILE USA, INC. | 44 | 5.5% |
| 06 | BRIGHTSPEED OF MISSOURI, LLC | 42 | 5.3% |
| 07 | EMBARQ MISSOURI, INC. DBA CENTURYLINK - MO | 38 | 4.8% |
| 08 | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MO | 38 | 4.8% |
| 09 | BRIGHTSPEED OF EAST MISSOURI, LLC | 38 | 4.8% |
| 10 | WINDSTREAM MISSOURI, INC. | 36 | 4.5% |
Important: these are initial assignees from NANPA CO-code records — the carrier a prefix was originally assigned to. Because of number portability, the current serving carrier of any individual number may differ.
Change history
Recorded events for this NPA- 2022-06-17 NPA 235 to Overlay NPA 573 (Missouri)
- 1996-01-07Area code 573 entered service (created from 314).
Planning letters & orders
Primary documents| Date | Document | Subject |
|---|---|---|
| 2022-06-17 | PL-596 ↗ | NPA 235 to Overlay NPA 573 (Missouri) |
| 1995-08-31 | IL-95-08-015 ↗ | NANP-SPLIT OF 314 (MISSOURI) NUMBERING PLAN AREA (NPA) |