While I've found no ancestral connections in Killarney for our family, the song came to mind this morning. 

"Christmas in Killarney" was first released by Dennis Day in 1950 and has been covered by many artists in the years since.

You might be thinking of the version by the Irish Rovers. 

Or the 1988 release by Anne Murray.

Here's a variation with fun video by the Rend Collective.

If you'd like to play and sing along, try this (free) easy score with lyrics.

MERRY CHRISTMAS to all from IGSI!