The incident happened around 7.05 pm on Friday July 31, and officers with Police Scotland Dumfries and Galloway Division received a report a man had been seen in the river near College Street in Dumfries.
James Carruthers, 48, was recovered from the water with the assistance of Nith Inshore Rescue, the Scottish Fire and Rescue Service and the Scottish Ambulance.
A Police Scotland spokesman explained Mr Carruthers was taken to Dumfries and Galloway Royal Infirmary, where he died a short time later.
His death isn’t being treated as suspicious, however police are appealing for witnesses to establish the full circumstances.
Detective sergeant Nadine Scott, of Dumfries CID said: “We’re appealing for help to trace his last movements just before he entered the water and anyone who witnessed this incident should contact us.”
Anyone with information should contact Police Scotland on 101 quoting incident number 3481 of July 31.