Massereene Upper is a barony in southwest County Antrim, Northern Ireland.

[2] It roughly matches the former district of Killultagh (Irish: Coill Ultaigh, meaning 'the woods of the Ulsterfolk').

[3] It includes settlements such as Crumlin, Glenavy, Lower Ballinderry, Maghaberry and Aghalee.

To its east lies Belfast Lough, and it is bordered by four other baronies: Massereene Lower to the north; Belfast Upper to the east; Castlereagh Upper to the south-east; and Iveagh Lower, Lower Half to the south-west.

This article related to the geography of County Antrim, Northern Ireland is a stub.