This is a very strange Hillfort, being so close to the King's Seat.
It's not very big (for a Hillfort) although the banks still stand to an impressive height of 2 metres in places. I would say the interior of the site is about 30 metres across..
As an aside, I picked up a very good guide to the Hill of Tara from the visitor's centre at Newgrange. A small booklet costing only 50 cents. They do similar booklets for Newgrange, Dowth and Knowth although they were sold out of the Dowth ones when I visited.
The weird figure eight formed by the proximity of the King's Seat and Cormac's House is fascinating. Within the pre-Christian Cormac's House stands the Lia Fail and a memorial gravestone to the Irish Rebellion of 1798.
Formerly a statue of St. Patrick stood here, in triumphant celebration of the defeat of the Heathens. When an attempt was made to take it away for renovation it fell apart, so a competition was held for local children to design another statue to stand by the path leading to the Hill of Tara.
Some locals disapproved of the resulting statue, due to his skirt not being long enough, so they pulled it down. A bog-standard St. Patrick now stands by the path instead, "biding his time" as a non-catholic local said to me on the Hill.