The Irish Rugby Football Union (IRFU) (Irish: Cumann Rugbaí na hÉireann) is the body managing rugby union in Ireland. The IRFU has its head office at 10/12 Lansdowne Road and home ground at Aviva Stadium, where Irish rugby union international matches are played. In addition, the Union also owns Ravenhill in Belfast, Thomond Park in Limerick and a number of grounds in provincial areas that have been rented to clubs.

Initially, there were two unions both founded in 1874 – the Irish Football Union had jurisdiction over clubs in Leinster, Munster and parts of Ulster; the Northern Football Union of Ireland controlled the Belfast area. 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 Board in 1886 with Scotland and Wales. (England refused to join until 1890).

Following the political partition of Ireland into separate national states, the Republic of Ireland (originally the Irish Free State then Éire) and Northern Ireland (a political division 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).

Andrew Trimble (born 20 October 1984) is an Irish rugby union player from Coleraine,County Londonderry, Northern Ireland. Trimble currently plays club rugby for Ulster and represents Ireland at international level.

He attended Coleraine Academical Institution, where he competed in the Ulster Schools Cup.

He plays at outside centre or on the wing for Ulster Rugby. In April 2006 he signed a new three year deal with Ulster. Trimble also played club rugby for Ballymena RFC in the AIB League and has represented Ireland Schools and the Ireland U21 team.

Due to a pre-season groin injury, however, he required surgery and missed part of the 2007–2008 season. He later underwent a hernia operation. On 30 April 2009, Trimble underwent surgery on his right knee to remove a piece of chipped bone.

Trimble, replacing the injured Brian O'Driscoll, made his debut for the Ireland national rugby union team during the 2005 IRB Autumn Internationals, against Australia. He started again the following week against Romania, securing victory for the Irish with two tries.