Pennington County, South Dakota, said most public-facing county offices will close Monday while officials respond to a cybersecurity incident affecting parts of its network.
The county said it is still determining the scope of the incident and working to restore systems safely, according to a release from the Pennington County State’s Attorney’s Office. Pennington County, anchored by Rapid City in western South Dakota, provides county government, courts, elections, jail and public safety services for one of the state’s largest population centers.
Critical life safety services remain operational, including 911 dispatch, the Pennington County Jail, the Juvenile Services Center, the Care Campus and other public safety operations, the county said.
Court operations, the county’s 24/7 Program, early voting and online or kiosk vehicle registration also remain available, the county said. Most other public-facing offices were set to close Monday.
The county said it is working with the South Dakota National Guard Cyber Incident Response Team, the South Dakota Fusion Center, the Cybersecurity and Infrastructure Security Agency and other partners as the investigation continues.
Officials have not confirmed an attack type, data theft, a ransom demand or a threat actor. The county has described the matter only as a cybersecurity incident affecting portions of its network.
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“Because this is an active investigation, there is very limited verified information available at this time,” the county said in the release.
National Guard cyber teams have increasingly been called to help state and local entities respond to serious network disruptions. In May, Winona County, Minnesota, said it was working with the Minnesota National Guard after a cyberattack disrupted county systems. St. Paul also sought Minnesota National Guard help during a 2025 cyberattack that affected city technology systems.
Officials have not said whether the incident involved ransomware, malware or unauthorized access, or whether any county data was accessed or taken. No public claims of responsibility were located by publication time. DysruptionHub had not received a response to questions sent to the county’s public information officer by publication time.
