“Ascaill Chúil na Saileach Highly likely to originate with Coolnasillagh, Ballinascreen, Derry, Cúil na Saileach ‘the corner / nook of the sallow(s)’ (PNI vol. V).” © Northern Ireland Place-Name Project, QUB. Coolnasille Avenue and Coolnasilla Park are both listed in the 1967 list of streets in the Belfast Street Directory.