Area code

CA

United States geographic area code, in service since 2025-01-31. Part of the 530/837 overlay complex — ten-digit dialing required.

Split from 530. Overlaid with 530 .

Statusin service

Introduced2025-01-31

JurisdictionCA, US

Local dialing1+10D

Time zonePacific

Last verified2026-09-17

Utilization 2.8% of assignable prefixes assigned As of 09/17/2026

0%22 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 2026-08-27, most recent 2026-09-02.

Area codes serve rate-center geographies, not municipal boundaries. “CA” identifies the jurisdiction, not an exact city footprint.

Top assignees

Ranked by assigned prefixes · initial assignee ≠ current carrier

Largest initial assignees in area code 837
Rank	Assignee	Prefixes	Share
01	MULTIPLE OCN LISTING	14	63.6%
02	ONVOY, LLC - CA	3	13.6%
03	WIDE VOICE, LLC - CA	2	9.1%
04	EXIANT COMMUNICATIONS LLC	2	9.1%
05	OPENTACT INC.	1	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

2023-08-08 NPA 837 to Overlay NPA 530 (California) overlay
2025-01-31Area code 837 entered service (created from 530).

Planning letters & orders

Primary documents

NANPA planning letters for area code 837
Date	Document	Subject
2023-08-08	PL-621 ↗	NPA 837 to Overlay NPA 530 (California)

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