The Washington County Sheriff says 12 people were arrested after breaking into park cabins at Afton State Park over the July 4th weekend.
The park has been closed due to the state government shutdown.
Sheriff Bill Hutton said the group broke into the park on Sunday night and caused about $35,000 in damages to park buildings, including burning one of the cabins and partially removing the roof.
Hutton said the damage was among the worst he's seen.
"It's not common at all," he said. "I would suspect or highly suspect that this would've not occurred if the park would've been open because they would've had personnel there."
The 11 adults and one 17-year-old were arrested Monday morning. They could face felony burglary charges.