Union County, Ohio officials yesterday confirmed they notified 45,487 people of a May 2025 data breach that compromised the following personal info:
- Names
- Social Security numbers
- Payment card info
- Financial account info
- Fingerprints
- Medical info
- State-issued ID numbers (e.g. driver’s license, passport)
“On May 18, 2025, the County detected ransomware on our computer network,” says Union County’s notice to victims. “Through our investigation, we determined that the cyber criminals accessed our network from May 6, 2025 through May 18, 2025, and took some County data.”
No cybercriminal group has publicly claimed responsibility for the attack as of time of writing. We do not know if the county paid a ransom or how attackers breached its network. Comparitech contacted Union County officials for comment and will update this article if they reply.
Union County is offering eligible victims free identity monitoring and $1 million in identity theft insurance through Experian. The deadline to enroll is December 31, 2025.
Ransomware attacks on US government
Comparitech researchers have logged 61 confirmed ransomware attacks on US government entities in 2025 to date. Those attacks compromised more than 431,000 records.
The attack on Union County, OH is the second largest such breach this year by number of records. It’s surpassed by the Pierce County, WA library system, which leaked 336,826 records in a breach claimed by Inc Ransomware.
This week, ransomware groups made two more claims of big breaches against US government agencies:
- Maryland’s Department of Transportation refused to pay a $3.4 million ransom to ransomware group Rhysida following an August 2025 data breach
- Pennsylvania’s Attorney General reported an August 2025 data breach. Ransomware group Inc says it stole 5.7 TB in the attack.
Ransomware groups made another 38 unconfirmed attack claims in 2025 to date. Those include attack claims that haven’t been publicly acknowledged by the targeted organizations.
Ransomware attacks on government entities can both steal data and lock down computer systems. They can disrupt any number of government systems from bill payments to court records and even emergency dispatch. Organizations must pay a ransom for the stolen data and to restore systems, or else they face extended downtime, permanent data loss, and putting data subjects at increased risk of fraud.
About Union County, OH
Union County is home to about 63,000 people in central Ohio. Not to be confused with the town of Union, Union County is part of the Columbus, Ohio metropolitan area, and its county seat is Marysville.
