Police are preparing a file for the Essex coroner after the death of an inmate at Chelmsford Prison.
Rocky Stenning, 26, was found in his cell at 15:00 BST on Thursday and pronounced dead at the scene.
The case is not being treated as suspicious, police said.
The Prison Service said: "Prisoner Rocky Stenning died in custody and as with all such deaths there will be an independent investigation by the Prisons and Probation Ombudsman."
Essex Police said: "His death is currently being treated as unexplained, but not suspicious."
This is believed to be the 11th person to have died in non-suspicious circumstances at the jail in the past five years.