Like all civil parishes in Ireland, this civil parish is derived from, and co-extensive with, a pre-existing parish of the
Church of Ireland. The
Archdiocese of Dublin held a number of
manors as cross lands. The manor of Finglas contained most of the area of the parish in four distinct parcels of 4,487 acres in total. The core of the parish is centered on the village of
Finglas, which lies within the barony of Castleknock. However, a substantial
exclave of the parish is situated within the neighbouring barony of
Nethercross. Since Kilreesk has a
cell toponym, this suggests that the church was a pre-
Invasion chapel of ease. This parcel of land contains six
townlands. Additionally, within the barony of Castleknock itself, two further parcels of land, that are distinct from the core around the village, are situated to the north of the barony. The larger parcel contains six townlands around the
Kilshane chapel of ease. The smaller parcel consists of a single townland and is surrounded by the civil parishes of
Mulhuddart and
Cloghran. ==Townlands==