South Dublin South Dublin South Dublin () is a county in Ireland, within the province of Leinster, and the Dublin Region, a successor to County Dublin, from which its name derives. South Dublin County Council is the local authority for the county. The county contains both dense suburbs of Dublin and stretches of unpopulated mountain. In 2011 it had a population of 278,749, making it the third most populous county in the state. South Dublin has an area of 222.74 square kilometres. It is bounded by Dublin City (15 km to the north east), the River Liffey (separating it from Fingal to
Newcastle, South Dublin Newcastle, South Dublin Newcastle () is a village in south-west South Dublin, Ireland. It is also a civil parish in the barony of the same name. It was the location of the castle of the barony, which in historical and official documents is described as Newcastle-Lyons. The area is still primarily rural in nature. Newcastle-Lyons is located at the junction of the R120 and the R405 regional roads. It lies approximately 3 km north of the N7 at Rathcoole, 6 km south east of Celbridge, and 9 km west of Tallaght. The village lies west of Casement Aerodrome (Baldonnell), the