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