Ontario Provincial Police have closed Highway 417 at Campbell Drive near Arnprior after a serious crash on Thursday afternoon.
Eastbound traffic in the area is being diverted to White Lake Road. The westbound lanes remain open.
Renfrew paramedics say the crash involved a single-vehicle with one occupant inside. No details on their condition were immediately available.
Police are advising drivers to be prepared to slow down when approaching the area.
Emergency services remain on scene.
This story will be updated.