Police were called to East Harbor State Park Beach Sunday afternoon to help a man who was found unresponsive in the waters.
Before emergency responders arrived at the scene, bystanders tried performing CPR on the man.
The Danbury Township Fire Department and EMS transported him to Magruder Hospital in Port Clinton.
Delmur Owens, 49, from Fremont was later pronounced dead at the hospital.
The cause of death is still pending investigation.
The Department of Natural Resources is leading the investigation while the Danbury Police Department and the Ottawa County Sheriff's Office also assisted on the scene.
Authorities are now urging visitors at state parks to be aware of local conditions, such as high or swift-moving water that can pose additional safety risks and to carefully follow safety instructions from park officials as well as take note of posted advisory signs.