County Armagh (Contae Ard Mhacha in Irish) is a county in Ulster. It is the smallest of the six counties that form Northern Ireland. County Armagh is known as the Orchard County because the land is so fertile for apple-growing. Its main town is Armagh, in the middle of the county, although Lurgan and Portadown, in the north of the county, each have larger populations.

The county borders Lough Neagh to the north, County Down to the east, County Tyrone to the north-west, and counties Louth and Monaghan, both in the Republic of Ireland, to the south and south-west respectively.