Both drivers were injured in an apparent alcohol-related crash on Route 68 south of Kenton Sunday night around 8:15.
The Findlay Post of the State Highway Patrol reports that Michael Hammond, 37, of Huber Heights, was driving a '94 Dodge Ram 250 van northbound when he rear-ended a '99 Honda Accord operated by Steve Slandzicki, 33, of Toledo.
Both men were transported to Hardin Memorial Hospital in Kenton.
Slandzicki was treated and released.
Hammond, who was not wearing his seat belt, suffered serious injuries. He was transferred to Grant Medical Center in Columbus.
Hammond's van went off the right side of the road, struck a ditch, and came to rest several hundred yards away in a field.
The Accord came to rest on the left side of the road.
The Hardin County Sheriff's Office, Kenton Fire Department, and BKP EMS assisted at the scene.
Troopers continue their investigation.