Kingscourt is in Ulster and east of the Shannon
Forget about Provinces. At the extremity of every Province, by definition, has to be Geographically ambiguous. After all they all have to meet each other at some point.
For example Roscrea is in Munster but its in the lower midlands.
Fenian seems to be talking about cultural history etc rather than geography, which is fine. But I'm talking geography. And if you were to split Ireland into the traditional 9 geographic segments of NE, E, SE, N, Mid, S, NW, W, SW then your town is in the middle. In no sense can it be considered to be in the NE.
Ireland is however a very irregular shape and on top of that so are the Counties. So although the bulk of Cavan is in the upper midlands, the stringy bit out towards Blacklion could almost make it into the NW.