Overview
The Irish Rugby Football Union (IRFU) is the body managing rugby union in the island of Ireland (both Republic of Ireland and Northern Ireland). The IRFU has its head office at 10/12 Lansdowne Road and home ground at Aviva Stadium, where adult men's Irish rugby union international matches are played. In addition, the Union also owns the Ravenhill Stadium in Belfast, Thomond Park in Limerick and a number of grounds in provincial areas that have been rented to clubs.
History
Initially, there were two unions: the Irish Football Union, which had jurisdiction over clubs in Leinster, Munster and parts of Ulster and was founded in December 1874, and the Northern Football Union of Ireland, which controlled the Belfast area and was founded in January 1875. The IRFU was formed in 1879 as an amalgamation of these two organisations and branches of the new IRFU were formed in Leinster, Munster and Ulster. The Connacht Branch was formed in 1900.
The IRFU was a founding member of the International Rugby Football Board, now known as World Rugby, in 1886 with Scotland and Wales. (England refused to join until 1890.)
Following the partition of Ireland in to what is now the Republic of Ireland (an independent country) and Northern Ireland (a region of the United Kingdom), the then Committee of the Irish Rugby Football Union decided that it would continue to administer its affairs on the basis of the full 32 Irish counties and the traditional four provinces of Ireland: Leinster (12 counties), Ulster (9 counties), Munster (6 counties), and Connacht (5 counties), as they had been whilst all in the United Kingdom.
From Wikipedia (CC BY-SA 4.0).