Monaghan gardaí believe the man whose body was found beside a burnt-out car off a mountain track near the village of Tydavnet late on Wednesday died accidentally.
Gardaí believe the man may have died of injuries sustained when the vehicle left the road and fell into a ravine.
The accident occurred near a bend on a narrow roadway which extends from the top of the Bragan mountain close to a "penal cross" site and the cross-Border Clogher route.
The area is about seven miles from Monaghan town and a short distance from the Border.
After a forensic examination at the scene, the body was removed for a postmortem examination at the Dublin City morgue.
Gardaí under Supt Joe Sullivan, of the Cavan/Monaghan Garda division, and Insp Pat McMorrow, Monaghan, sealed off the area yesterday as detectives examined the vehicle.
Last night, gardaí said that they were awaiting an autopsy report and until they had the results they could not determine the exact cause of death. The indications from the scene, however, were that foul play was not suspected.
It is understood that the vehicle had a Northern registration number. While the body has not been formally identified, gardaí believe the victim came from Dungannon, Co Tyrone.
They said he might be formally identified today.