314
Area code

MO

United States geographic area code, in service since 1947-01-01. Part of the 314/557 overlay complex — ten-digit dialing required.

Created 573. Created 636. Created 557. Overlaid with 557 .

Statusin service
Introduced1947-01-01
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 2001-01-17, most recent 2026-05-21.

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
Largest initial assignees in area code 314
RankAssigneePrefixesShare
01 SOUTHWESTERN BELL 255 31.9%
02 NEW CINGULAR WIRELESS PCS, LLC - IL 101 12.6%
03 T-MOBILE USA, INC. 94 11.8%
04 CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MO 53 6.6%
05 MCIMETRO ACCESS TRANSMISSION SERVICES LLC - MO 51 6.4%
06 ONVOY, LLC - MO 50 6.3%
07 TELEPORT COMMUNICATIONS AMERICA, LLC - MO 26 3.3%
08 LEVEL 3 COMMUNICATIONS, LLC - MO 24 3%
09 AMERICAN MESSAGING SERVICES, LLC 20 2.5%
10 PAETEC ITEL, LLC 19 2.4%

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

Planning letters & orders

Primary documents
NANPA planning letters for area code 314
DateDocumentSubject
2021-10-28 PL-567 ↗ NPA 557 to Overlay NPA 314 (Missouri)
2021-01-08 PL-556 ↗ Transition to 10-digit dialing (for 988 as 3-digit access to National Suicide Prevention Lifeline) – supersedes PL-544
2020-08-17 PL-544 ↗ Transition to 10-digit dialing (for 988 as 3-digit access to National Suicide Prevention Hotline
2001-10-05 PL-303 ↗ Suspension of the 314 NPA Relief (Missouri)
2001-05-09 PL-279 ↗ NPA 557 Overlay of NPA 314 Implementation Date and Dialing Plan Change (Missouri)
2001-02-14 PL-261 ↗ New NPA 557 to Overlay NPA 314 (Missouri)

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