Oneillland West lies in the north of the county on the south-western shore of Lough Neagh and the border of Tyrone. It is bordered by five other baronies: Armagh to the west; Dungannon Middle to the north-west; Oneilland East to the north-east; Orior Lower to the southeast; and Kinelarty to the south.
Oneilland West along with Oneilland East used to form the barony and Plantation of Ulster precinct of Oneilland. When it was split in two, Oneilland West consisted of the barony west of the River Bann, corresponding to the ancient Irish districts of Oneilland and Clancann.
Mount Roe house is located in this barony. The Battle of the Diamond on 21 September 1795, which led to the foundation of the Orange Order, occurred within this barony at The Diamond crossroads.
Towns and villages
Towns and villages of Oneilland West are:
- Armagh (split with barony of Armagh)
- Clonfeacle (split with baronies of Armagh and Dungannon Middle)
- Grange (split with barony of Armagh)
- Kildarton (split with barony of Fews Lower)
- Killyman (split with barony of Dungannon Middle)
- Kilmore (split with barony of Orior Lower)
- Loughgall (split with barony of Armagh)
- Mullaghbrack (split with barony of Fews Lower)
- PRONI Baronies of Northern Ireland
- PlaceNames NI: Oneilland West
- "Oneilland West". Placenames Database of Ireland. Department of Community, Rural and Gaeltacht Affairs. http://www.logainm.ie/294.aspx. Retrieved 8 June 2011.
- PRONI Civil Parishes of County Armagh
- Baronies and civil parishes of County Armagh