Tullyhogue Fort is an Iron Age hillfort about 5 kilometres south of Cookstown that served as the inauguration site of the O'Neill kings of Ulster, the most powerful Gaelic dynasty in Ireland, from the 12th century until the Elizabethan conquest in the early 17th century. The fort consists of two concentric earthwork rings on a hilltop, enclosing a central area where the inauguration ceremonies took place.
The site is freely accessible and managed by the Northern Ireland Environment Agency. The walk up to the hilltop from the car park takes about ten minutes and the views over the surrounding Tyrone countryside are good. Interpretive panels at the site explain the history of the O'Neill dynasty and the significance of the inauguration rites. The earthworks themselves are well-preserved — the banks are still several metres high — and give a strong sense of the site's original enclosure.