It happened Saturday around 10:00 a.m. near the Dupont Experimental Station.
Police received a report that there was a man in the river and authorities arrived to find the victim clinging onto a rock nearby.
Rescue crews were able to pull the man from the river and lift him up a 300 foot embankment.
The victim was taken to Christiana Hospital in guarded condition for hypothermia.
No word on how the man got stuck in the river.