Tom a Chaisteil basically means castle on a hill and this site is on the eastern side of Beinn Mhor (hill not cairn.) From Beinn Mhor cairn we walked eastwards until the small hillock and headed north. By this time the weather was closing in, underfoot conditions were boggy and overhead it had turned very cloudy and wet. Still we plodded north until the wee hill at the side of the big hill came into view. Another single tree, which sits in the middle of the fort on the wee hill, is what to aim for. We squelched past the eastern defences and entered the fort from the north.
The eastern defences/walls have fallen over the side of the cliff. Most of the rest of the circular wall can be seen but it is almost all in a fallen state. We approached from the north but the entrance is in the west. A trench, as mentioned by Canmore, is some 10 meters to the north. Not much remains except for a lonely tree located within the 33 by 31 meters fort. Like Hob we spotted circular features which could possibly have been hut circles. After a good look round, why are places so impressive in the rain and mist!, it was back to plodding across the heather to the forest gate from which we started.
From this gate the eastern cliff can easily be seen to the north west. This is a fantastic place regardless of weather and with that it was back down to the car at Glenbeg, the end of a long, injury free, but brilliant day.
Visited 9/7/2016.