Why was northen Ireland separated from Ireland?

Answer 1

Northern Ireland at the time of the Anglo-Irish Treaty (1921) was home to more unionists (those who wished to remain apart of the UK) than nationalists (those who sought freedom and independence from the British Empire). While the Irish negotiators of the Treaty sought to make Ireland completely independent, the six counties (Derry, Down, Tyrone, Antrim, Armagh and Fermanagh) with the highest ratio of unionists to nationalists were surrendered to British rule in a compromise to give the remaining 28 counties a dominion status, and later, republic status.