Belfast Upper is a barony in County Antrim, Northern Ireland. To its east lies the barony of Belfast and Belfast Lough, and it is bordered by five other baronies: Belfast Lower to the north-east; Antrim Upper to the north-west; Massereene Lower to the west; Massereene Upper to the south-west; and Castlereagh Upper to the south. The Forth River flows through both Belfast Upper and Lower. The most prominent hills in the barony are Black Hill and Lyle's Hill.