Maricopa County Data Breach History

This page tracks the Maricopa County data breach history and cybersecurity incidents affecting Maricopa County (United States). BreachHistory currently indexes 1 publicly disclosed or catalogued incident spanning 2020, with approximately 633 thousand records reported as exposed across all indexed events. These totals may include overlapping datasets or third-party estimates and should not be interpreted as unique affected users.

The Maricopa County breach timeline includes major data breaches, cyber attacks, data leaks, credential exposures, API abuse, and other security incidents. Each incident provides details on the estimated records exposed, attack method, affected data types, and supporting public sources. Currently, 0 incidents are company-confirmed.

Largest Maricopa County Data Breaches

The largest indexed incidents include the 2020 Maricopa County — 633,000 voter registration files scraped pre-election (FBI/…. Record counts originating from threat actors or leak sites should be treated as estimates unless confirmed by Maricopa County or a regulator. Below is the list of large data breaches:

• 2020 2020 Maricopa County — 633,000 voter registration files scraped pre-election (FBI/WH declassified 2026) — about 633.0K records exposed · Catalogued incident

What Information Was Exposed?

Depending on the incident, exposed data may include email addresses, passwords, phone numbers, names, profile information, account identifiers, and other personal information (PII). The exact data varies between incidents, so review each breach page before assuming your information was affected.

Maricopa County Data Breach 2026

At the time of this update, no Maricopa County data breach has been catalogued for 2026. New incidents are added as official disclosures, regulatory filings, or credible cybersecurity reports become available.

What To Do If You Were Affected

If you believe your account may have been involved in a Maricopa County data breach, change any reused passwords, enable multi-factor authentication (MFA), monitor your account for suspicious activity, and be cautious of phishing emails or fake breach notifications.

This Maricopa County breach history is maintained by BreachHistory using public disclosures, regulatory filings, security research, and clearly labelled third-party claims. For the complete breach timeline, records exposed, incident details, and AI Breach Risk Score, explore the sections on this page.