Letterkenny, nicknamed "the Cathedral Town", is the largest and most populous town in County Donegal, Ireland. It lies on the River Swilly in East Donegal and has a population of 19,274. It is the 36th-largest settlement in all of Ireland by population (placing it ahead of Sligo, Armagh and Killarney) and hovers around being the 13th or 14th largest settlement by population in the historic province of Ulster (most of which comprises the separate jurisdiction of modern-day Northern Ireland). Along with the nearby city of Derry, Letterkenny is considered a regional economic gateway for the north-west of Ireland. Letterkenny acts as an urban gateway to the Ulster Gaeltacht, similar to Galway's relationship to the Connemara Gaeltacht.