Castleknock is a suburb
The word suburb mostly refers to a residential area, either existing as part of a city or as a separate residential community within commuting distance of a city . Some suburbs have a degree of administrative autonomy, and most have lower population density than inner city neighborhoods...

 of Dublin, Ireland
Ireland is an island to the northwest of continental Europe. It is the third-largest island in Europe and the twentieth-largest island on Earth...

. It is in the west of the modern administrative county of Fingal
Fingal is a county in Ireland. It is one of three smaller counties into which County Dublin was divided in 1994. With its county seat located in Swords, it has a population of 239,992 according to the 2006 census...

 within the traditional county of Dublin
County Dublin
County Dublin is a county in Ireland. It is part of the Dublin Region and is also located in the province of Leinster. It is named after the city of Dublin which is the capital of Ireland. County Dublin was one of the first of the parts of Ireland to be shired by King John of England following the...

. It is located 8 km (5 mi) west of the centre of Dublin.

Castleknock is also a civil parish
Civil parish
In England, a civil parish is a territorial designation and, where they are found, the lowest tier of local government below districts and counties...

 in the barony of the same name. The Barony of Castleknock
Barony of Castleknock
The Barony of Castleknock meaning "Cnucha's Castle" is one of the baronies of Ireland, an historical geographical unit of land. It takes its name from the suburban village of the same name - Castleknock. The town with the biggest population in the barony is Blanchardstown.-Location:It is one of...

 was originally a feudal lordship created in the 12th century for the Tyrell family.