Ulster is one of the traditional provinces of Ireland.
Six of Ulster's nine counties: Antrim, Armagh, Down, Fermanagh, Londonderry and Tyrone form Northern Ireland, remaining part of the United Kingdom after the partition of Ireland in 1921. Three Ulster counties: Cavan, Donegal and Monaghan form part of the Republic of Ireland. Many inhabitants refer to the six-county Northern Ireland as "Ulster".
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