Thank you. The place just seems to be archaic to define.
I had come across one reference on the internet for
Slieveenagh at
http://www.sip.ie/sip064/Currow.htmlIt lists "Townlands of Killeentierna." Under the letter S it has:
Sandville: Shanavullen: The old mill Slieveenagh: Springmount: Cnocearagh
I believe that should be actually divided into 2 entries:
Sandville: Shanavullen: The old mill
Slieveenagh: Springmount: Cnocearagh
I'm not sure what the source of that information is though.
I did confirm that Shanavullen meant "old mill." I was having trouble trying to translate Slieveenagh (using Gaelic dictionaries on-line) into something like Springmount. I think I was coming up with something like "mount heath."
There is a Slievenagh in County Antrim, but that seems just too far away. Also, I couldn't find it translated from Gaelic anywhere on the net.