Colin Barnfather, 54, has been reported missing in Derby in the East Midlands.
Officers believe he travelled to Lochaber in the Highlands in late September to hill-walk and camp.
It is thought he planned to walk in the Kinloch Hourn area of the west coast.
Mr Barnfather is 5ft 8in and of medium build with short grey hair. He is thought to have been wearing outdoor clothing and using a single person green tent.
Police want to hear from anyone who may have seen or spoken with Mr Barnfather or spotted a blue Honda motor car parked in the area.
Anyone with information is asked to contact police on 101.