I have found no evidence of one, some claim that the Fómhoir Elatha is a god of the moon. Others say that Caer Ibormeith or Niamh are lunar goddesses, but I have found no evidence of these. I have found very little information about Laír Báln, which was supposed to be the moon, translating into "white mare". I can't find any info or even a wiki on Láir Báln though and don't even know the mare's gender. Any thoughts?
Óenach - Irish Lunar deity?
A Celtic Reconstructionist Assembly