Named Donegal after its chief town. He also created county Tyrone at the same period, from part of the ancient Tyrone. Galway, Roscommon, Mayo, and Sligo. According to The Book of The Abbey of Dousk , before the Invasion, there were 180 Triochas or Cantreds, now called Baronies. Now, back to our topic.
Provinces are the largest division and generally reflect the ancient Irish kingdoms.
O'Neill in Ulster, O'Brien in Munster, O'Connor in Connaught, and MacMurrough in Leinster. The county is the principal unit of local government. There are twenty-six in the Republic of Ireland and six counties in Northern Ireland, for a total of 32 counties. Most document collections are organized on a county basis. The county network was begun in the 12th century and was completed in 1606 with the addition of County Wicklow.