BreachCensus

Marshfield Clinic Health System

healthcareHealthcareUnited States of America

Marshfield Clinic Health System is a healthcare organisation in Wisconsin. It appears on the HHS OCR breach portal with 1 confirmed incident; the most recent notice was filed on November 7, 2025.

Data as of August 28, 2026.

Confirmed incident

US-WI — Hacking/IT Incident

Disclosed
November 7, 2025
Records affected
35,952

Timeline

  1. November 7, 2025
    Reported to regulator Regulator

    HHS OCR breach portal listing: Hacking/IT Incident; Email

    source

Litigation

  • Possible litigation — multiple candidate dockets found, not yet resolved to a single case.
What a Wisconsin notice means

Governed by Wis. Stat. §134.98. No state agency must be notified. Affected individuals must be told within 45 days, and the national credit bureaus too when 1,000 or more people are notified; DATCP lists breaches reported to it or found to affect Wisconsin consumers.

Note: the count is Wisconsin residents only when published, not a total; many notices do not include one.

Wisconsin breach-notification register ↗