The Council of Ireland was a statutory body established under the Government of Ireland Act 1920 as an all-Ireland law-making authority with limited jurisdiction, initially over both Northern Ireland and Southern Ireland, and later solely over Northern Ireland. It had 41 members: 13 members of each of the Houses of Commons of Southern Ireland and of Northern Ireland; 7 members of each of the Senates of Southern Ireland and of Northern Ireland; and a President chosen by the Lord-Lieutenant of Ireland. It never met and was abolished in 1925.

The Sunningdale Agreement was an attempt to establish a power-sharing Northern Ireland Executive and a cross-border Council of Ireland. The agreement was signed at Sunningdale Park located in Sunningdale, Berkshire, on 9 December 1973. Unionist opposition, violence and general strike caused the collapse of the agreement in May 1974.