Perhaps this may be of some use. It's a map of the political divisions of Ireland circa 1066. I've shown the boundaries between the provinces (in blue), major provincial sub-divisions (in green), and regional overkingdoms in red. These are all labelled in their appropriate colour. I cannot claim complete accuracy, but it is based on recent scholarship done by Paul McCotter on the trícha cét, the Irish cantredal system and basis for administration (and are outlined here in black). I thought it may be useful for anyone who wished to compile a large Britannia Map, or perhaps for those who want more accuracy in provincial and sub-provincial boundaries. Names for the trícha cét themselves (where present) are in later Norman forms, but each are numbered and I intend to put up their native names along with their number at a later stage.