The Irish: tríocha céad, also known as Irish: trícha cét, meaning "thirty hundreds", was a unit of land-holding in eleventh and twelfth century Ireland.[1] The term appears to relate to the number of troops an area could raise.[1]
Described as a "spatial unit of royal tenure, taxation, local government, and military levy", Irish: the trícha cét largely corresponded to a local petty kingdom ruled by a petty king. A minority, however, were ruled by a Irish: [[Taoiseach#Origins_and_etymology|taisaig]] (leader) or an Irish: airríg (governor), appointed by a superior kings.
In the province of Ulster, a Irish: tríocha céad was subdivided into roughly twenty-eight Irish: baile biadhtaigh, meaning "lands of a food-provider", and around 463 Irish: seisrigh, meaning "six-horse plough-teams".[1]
During the eleventh century, the system became established across the island, a refinement on a pre-existing system.