Tullyhogue Fort, also spelt Tullaghoge or Tullahoge (from Middle Irish Tulach Óc meaning "hill of youth" or "mound of the young warriors"), is large mound on the outskirts of Tullyhogue village near Cookstown, County Tyrone, Northern Ireland. It has a depressed centre and is surrounded by trees. It is an ancient ceremonial site where chieftains of the O'Neill dynasty of Tyrone were inaugurated.
It is a State Care Historic Monument sited in the townland of Ballymully Glebe, in the Cookstown District Council area, at grid reference: H8250 7430. The inauguration site is a Scheduled Historic Monument at grid ref: H8251 7428.
The date of the construction of Tullyhogue fort is not known, however it is believed to have held great significance from early times, possessing a form of ritual importance long before the O'Neills became associated with the site.
Tullyhogue rath was originally associated with the Uí Tuirtri of Airgialla, and then with the O'Hagans between the 11th and 17th centuries. The O'Hagans dwelt at the site and became its hereditary guardians, with their burial place at Donaghrisk situated at the bottom of the hill. In the later medieval period it became the inauguration site of the O'Neill dynasty, where the title "the O'Neill", was bestowed upon each new lord. The inauguration was carried out by the heads of the O'Cahan and O'Hagan. O'Cahan, the O'Neill's principal sub-chief, would throw a golden sandal over the new lord's head to signify good fortune. O'Hagan, being the hereditary guardian of Tullyhogue, would place the shoe on the O'Neill's foot and present him with a rod of office.
Hugh O'Neill's inauguration in 1595 was the last such event for an O'Neill to take place at Tullyhogue. The last coronation that is claimed to have taken place at Tullyhogue was that of Sir Phelim O'Neill in 1641, however it was later rejected.