Mono County

Disclosed Sep 25, 20202,850 affectedConfirmed

The covered entity (CE), Mono County, reported that it experienced a cyber-attack that affected the electronic protected health information (ePHI) of 2,850 individuals. The ePHI (ePHI) involved included names, dates of birth, lab results, and other treatment information. The CE notified HHS, affected individuals, the media, and posted substitute notice on its website. As a result of OCR’s investigation, the CE implemented additional technical safeguards and retrained its staff.

What is known

People affected	2,850 (as reported to HHS)
Disclosed	Sep 25, 2020
Happened	Apr 9, 2020
Attack	Hacking
Data exposed	NamesHealth
Sector	Government · US
Status	Confirmed

Sources

Official noticeoag.ca.gov

California Attorney General breach notice: Mono County

Official noticeocrportal.hhs.gov

HHS OCR breach report (archive, resolved): Mono County (Healthcare Provider, CA)

Notices filed

Residents of CASep 25, 2020

California AGCount not stated

TotalSep 25, 2020

HHS archive2,850 people

History of this record

attack2026-09-25

unknown to hackingby backfillSource

data_types2026-09-25

[] to ["names","health"]by backfillSource

records_basis2026-09-25

empty to hhsby backfillSource

records2026-09-25

empty to 2850by backfillSource

summary2026-09-25

empty to The covered entity (CE), Mono County, reported that it experienced a cyber-attack that affected the electronic protected health information (ePHI) of 2,850 individuals. The ePHI (ePHI) involved included names, dates of birth, lab results, aby backfillSource

Added2026-09-25

First recordedby backfillSource

First seen 2026-09-25 (California AG), confirmed by California AG. Record counts are as reported. Not legal advice.

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