Oneilland

Oneilland Uí Nialláin(Irish)
Location of Oneilland, County Armagh, in present-day Northern Ireland. It was based on the Irish district of Uí Nialláin.
Sovereign state	United Kingdom
Country	Northern Ireland
County	Armagh

Oneilland (from Irish: Uí Nialláin, meaning "descendants of Nialláin") is the name of a former barony in County Armagh, present-day Northern Ireland. It covers the northern area of the county bordering the south-eastern shoreline of Lough Neagh. At some stage the barony was divided into Oneilland East and Oneilland West.

The barony of Oneilland—also recorded as Oneilan—derives its name from the anglicisation of the ancient Irish district of Uí Nialláin, which was named after the Irish sept of the same name. Its territory however is based upon three such districts: "Oneilan, Clanbrassil, and Clancann". Clanbrassil and Clancann both lay along the southern shoreline of Lough Neagh, with the River Bann forming the boundary between them, with the former on the east side and the latter on the west side. Oneilan lay south of Clancann also west of the river.

The Uí Nialláin were a sept of Clan Cernaich, and they ruled from Loch gCál, modern-day Loughgall. Along with the Uí Bresail and Uí Echdach, they were amongst the main dynasties to arise from the split in the 8th century of Airthir, one of the nine kingdoms of Airgíalla. The land of the Uí Echdach corresponded to the modern barony of Armagh. The land of the Uí Bresail, recorded as "Clanbrassil" in English, as well as that of "Clancann" both lay in the modern barony of Oneilland East along the southern shore of Lough Neagh. The River Bann

The related Ó hAnluain (O'Hanlon) sept were for a couple of centuries chiefs of Oneilland, after which they ruled for several centuries as chiefs of a much reduced Airthir, which by then corresponded to the modern baronies of Orior Lower and Orior Upper, which derive their name from it.

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