After reading Rhiannon's folklore about this place I've always wanted to go. Check out a bit of Arthurian legend etc.
This is a stunning place with stunning views and friendly cows. I approached from the west heading north from Alyth (not a very good baker) on the B954 stopping between the Hill Of Loyal (west) and Barry Hill (east). The western climb is a steep effort but worthwhile from my point of view as it showed that my fitness is coming back. Plus it takes you past the small pond. The fort itself is some 78 meters in length and 23 meters wide and now contains some wind shelters built with rampart stones. On the south east rampart the entrance can be found.
Several ramparts have been constructed some reaching four meters in height and some 15 meters in width. The inner defences are made from rocks and anything they could get their hands on. Defences on west are natural as I found out!
The pond on the western side (is fenced) is inside the ramparts on a plateau and once again old Mr Easson was right as he mentioned this place as well. Canmore described it as an outer fort. So they had a water supply.
From the air this place must be stunning as the Canmore notes state. Being the last stop of a very long and early day I wandered all around the fort several times. This fort is a remarkable achievement, like Barmkyn up in my corner, and simply amazed me. Best to look for yourselves if possible.
By the time I'd finished wandering it was getting dangerously dark so it was back down the hill and into the car to head back up to the NE.
On the top of Barry-hill near Alyth in Perthshire.. there was a fort of very great strength..
The tradition of the country, which is probably derived from the fiction of Boyce, relates that this vast strength of Barry-hill was the appropriate prison of Arthur's queen, the well known Guenever, who had been taken prisoner by the Picts.
About a quarter of a mile eastward, on the declivity of the hill, there are some remains of another oval fort, which was defended by a strong wall, and a deep ditch. The same tradition relates, with similar appearance of fiction, that there existed a subterraneous communication between these two British forts, on Barry-hill.
p14 of 'A History of the Highlands and of the Highland Clans' by James Browne (1838), now digitised at Google Books.
Slightly more excitingly than just linking the enclosure with the fort, Angus's 'Forfarshire Illustrated' (1843) suggests the following about the nearby Castle of Inverquiech: Beneath the fragment of the Castle there is a vault, which is popularly believed to be the entrance of a subterraneous passage, which communicates with the old British hill-fort, on the summit of Barry Hill, in the adjoining parish of Alyth.
The New Statistical Account adds a bit more (v10 for Perth, 1845, p1118):
Like other places of the same kind, it is the scene of innumerable legends, which agree in representing it as the residence or prison of the infamous Vanora or Guinevar, who appears in the local traditions under the more homely appellation of Queen Wander, and is generally described as a malignant giantess. This tradition perhaps arose from the vicinity of the celbrated sepulchral stones at Meigle, which are generally considered as the remains of the monument of Vanora..
The Meigle stones are beautifully carved Pictish stones, which are supposed to depict Vanora's unpleasant end, among other things.