The Electoral (Amendment) Act 2009 (No. 4) is a law of Ireland which amended electoral law, including revisions to Dáil constituencies and European Parliament constituencies in light of the 2006 census. The new European Parliament constituencies were used at the election in June 2009. The revision to Dáil constituencies took effect on the dissolution of the 30th Dáil on 1 February 2011 and a general election for the 31st Dáil on the revised constituencies took place on 25 February 2011.