Castlereagh (County Down barony)

Castlereagh is the name of a former barony in County Down, present-day Northern Ireland. It spanned the north-eastern area of the county bordering the baronies of: Ards to the east; Belfast to the north; Iveagh to the west south; and Dufferin, Kinelarty, and Lecale to the south. By 1841 the barony was divided into Castlereagh Lower and Castlereagh Upper.