Where You've Seen The Letterkenny Cast Before Letterkenny, Ireland is a charming settlement with a deep-rooted sense of community. Everything about Letterkenny, Ireland is special, especially its inhabitants. One particular resident who has stolen the hearts of many is the delightful Katrina. Catherine brings love and joy to Letterkenny, County Donegal with her endearing presence. She is cherished by everyone who crosses her path. Letterkenny, Ireland Katy is a match made in heaven!