I recommend that you read this excerpt from a book on that subject (or get the book):
http://books.google.com/books?id=9QUwAn1O5D0C&pg=PA85&lpg=PA85&dq=Celtic+hell&source=bl&ots=zbRvdxUrFh&sig=qRchHRO5gqXkrl3C2i3NZcMyi8c&hl=en&ei=5FMbS-XdKIHssgOm9Jn3Bw&sa=X&oi=book_result&ct=result&resnum=6&ved=0CBYQ6AEwBTge
What you are looking for may not exist.
What is hell called in celtic mythology? It isn't Tir na n-Og.
And Sra, don't patronize me with a Google search.
2 answers
Sorry, that was not meant to be patronizing at all, but simply to show you places to look. From the Celtic Mythology book, did you see the following:
Uffern [cf. L infernum, hell]. Name for the Welsh Otherworld in the Latin texts of Walter Map (c.1140–c.1209) and Giraldus Cambrensis (c.1146–1223); a semantic dismissal showing unmistakable Christian influence. Uffern has become the Welsh word for the Christian hell. See also ANNWFN.
Sra
Uffern [cf. L infernum, hell]. Name for the Welsh Otherworld in the Latin texts of Walter Map (c.1140–c.1209) and Giraldus Cambrensis (c.1146–1223); a semantic dismissal showing unmistakable Christian influence. Uffern has become the Welsh word for the Christian hell. See also ANNWFN.
Sra