Notts Police were called to the scene on Ollerton Road, Carburton, near Worksop, just after 12 noon.
The car had left the road and entered the river.
The male driver was pronounced dead at the scene and there were no other casualties.
Police closed the road at the junction of Sparken Hill and Carburton crossroads while they carried out their inquiries.
They do not think any other vehicle was involved.
Anyone with information about the incident should call Notts Police on 101.