Detective Inspector Diane Davies of Dyfed-Powys Police said: "This gentleman's body was recovered with dignity from the scene.
"We are urgently trying to identify him so that his next of kin can be informed and arrangements made for his funeral.
"We have been in contact with all other police forces throughout the country but potential identities have now been exhausted."
The man was believed to be aged about 60. He was white, 1.8m tall with ginger or fair hair, wore glasses, and weighed 94kg, say police.
He had a distinctive curved scar across his stomach and his gall bladder had been removed.
The man was wearing layers of clothing suitable for cold weather conditions and was carrying a money pouch and a rucksack.
Police say a post mortem examination has been conducted and they are waiting for final results.
The death is unexplained but is not being treated as suspicious.
