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