Area Code Overview

Area code 557 is a geographic telephone area code in Missouri that went into service on August 12, 2022. The geographic regions covered by this area code overlay has a population of approximately 1,272,624.

Overlay and Dialing Rules

Area Code: 557
State: Missouri
Type: General Purpose Code
In Service Date: August 12, 2022
Overlay Complex: 314/557
Local Dialing Plan: This area does require you to dial the area code when calling locally.

Estimated Number of Assigned Phone Numbers in Area Code 557

This area code is ranked 340th out of 363 nationwide in estimated assigned phone numbers. Within the state territory it serves, it is ranked 7th out of 9.

637,000

Estimated Service-Type Mix of Assigned Phone Numbers in Area Code 557

Total assigned 637,000

Wireless

248,000 assigned

38.93%

Wireline and VoIP

235,000 assigned

36.89%

Other / Unclassified

154,000 assigned

24.18%

Estimated Share of Wireless Numbers Originally Assigned to Each Carrier in Area Code 557

Estimated assigned wireless phone numbers: 248,000

Numbers may later be ported to another carrier, but this chart reflects original number assignment, not current subscriber share.

AT&T Wireless 208,000 (83.87%)

Verizon Wireless 37,000 (14.92%)

T-Mobile 3,000 (1.21%)

Estimated Share of Wireline and VoIP Numbers Originally Assigned to Each Carrier in Area Code 557

Estimated assigned wireline and VoIP phone numbers: 235,000

Onvoy 180,000 (76.60%)

Spectrum 22,000 (9.36%)

NUSO 9,000 (3.83%)

Bandwidth 8,000 (3.40%)

Telnyx 5,000 (2.13%)

TERRA NOVA TELECOM INC. 3,000 (1.28%)

MCIMETRO ACCESS TRANSMISSION SERVICES LLC - MO 2,000 (0.85%)

Vonage 2,000 (0.85%)

Comcast Business 1,000 (0.43%)

LEAP TELECOM, LLC 1,000 (0.43%)

Peerless Network 1,000 (0.43%)

WIRETAP TELECOM, LLC. 1,000 (0.43%)

Other / Unclassified Assigned Numbering in Area Code 557

Estimated assigned other or unclassified phone numbers: 154,000

TELEPORT COMMUNICATIONS AMERICA, LLC - MO 142,000 (92.21%)

HD CARRIER LLC 3,000 (1.95%)

IP HORIZON LLC 3,000 (1.95%)

FIVE9, INC. 2,000 (1.30%)

CALLWORKS CORPORATION 1,000 (0.65%)

E. RITTER COMMUNICATIONS, LLC 1,000 (0.65%)

U.S. TELEPACIFIC CORP. DBA TPX COMMUNICATIONS 1,000 (0.65%)

WAVENATION, LLC 1,000 (0.65%)

Cities and Towns in Area Code 557

Creve Coeur, Missouri Kirkwood, Missouri La Due, Missouri Mehlville, Missouri Oakville, Missouri Sappington, Missouri St. Louis, Missouri

These geographic regions are also served by area code 314.

How These Figures Were Built

These figures are estimates based on public phone-number assignment records. They are meant to show the likely mix of assigned phone numbers associated with area code 557, not live customer counts.

Some providers may have assigned phone numbers tied to this area code even if they do not actively market or sell service locally. These figures reflect public number-assignment records, not confirmed local service availability.

They also do not reflect number portability at the individual phone-number level, so some numbers may now be used on a different network or by a different provider than the original assignment records suggest.

Population data and locality matching provided by GeoNames.

Last refreshed: April 15, 2026 6:22 pm