I've noticed that for the 1901/1911 censuses that there are:
Two Ballyduff and two Ballyegan DEDs in Kerry.
Two Claudy DED's in Derry.
Two Ballinalack in W. Meath.
There are two DEDs in Kilkenny called Muckalee. One outside the city and one in the south of the county. Isn't that weird?
Two Gorteen DED's in Offaly.
Two Clogher DEDs in Mayo.
Two Clooneys and two Kilmurry DEDs in Clare.
Two Clonea in Waterford.
Two Ballykeel in Down.
Donegal has two DEDs called Gleneely and two called Aughrim.
Two Enagh in Monaghan.
Two Whitechurch in Wexford.
and I'm sure there are more as I gave up checking...
So, if we look at this page in the census:
The townlands cover three different DEDs, which I find very confusing...
Now I understand that there is an intermediary district between county and ded which explains things - is it called barony? But is it just a coincidence that so many deds have the same name?