At the beginning of the Anglo-Norman invasion all Ireland is found to be divided into cantreds. This spatial unit was the successor to the earlier trÝcha cÚt. This is an attempt to define the role of the cantred in the Anglo-Norman period and after. The cantred was, in many cases, used as a unit of infeudation. Thereafter it played a specific role in all royal counties and in many liberties. In the royal counties a `standard┐ system of local administration evolved in which it has a clearly defined role. In the liberties its role varied: sometimes like that in the royal counties, sometimes ceasing to have any function. In the royal counties and in many liberties it had a clear role:┐ (i) a judicial function; (ii) policing; (iii) civil administration; and (iv) taxation. Generally, cantredal boundaries remained static but there were a few exceptions. Its decline is traced as part of the general decline in colonial local administration. Finally, the role of the cantred is examined in the uncolonised parts of Ireland.