Sinn Féin TD Caoimhghín Ó Caoláin has confirmed he will not stand in the next general election.
Mr Ó Caoláin was first elected a TD for the party in 1997 and was the first Sinn Féin representative to be elected. He has been re-elected every election since.
Speaking at a meeting of councillors and activists in Cavan on Wednesday night, Mr Ó Caoláin said he was standing aside to facilitate a younger generation to come forward.
Mr O’Caolain served as the party’s sole representative from 1997 to 2002 and served as the party’s Dáil leader until 2011.
A former bank official, he was first elected to Monaghan County Council in 1985.
He was general manager of An Phoblacht/Republican News from 1982 to 1985 and director of elections for Kieran Doherty, one of the H-Block hunger- strikers, who won a Dáil seat in 1981.