Merrion Street is a major Georgian street on the southside of Dublin, Ireland which runs along one side of Merrion Square. The garden entrance of Leinster House is located on the street, as is Irish Government Buildings, formerly the Royal College of Science for Ireland. Some reports suggest that Arthur Wellesley, 1st Duke of Wellington was born in his family's Mornington House on the street. The house is now a hotel.
The street was originally lined on both sides by Georgian houses. However between 1904 and 1922 all the houses on one side of the street were demolished and replaced by the Royal College of Science for Ireland, which was designed by Sir Aston Webb. The term Merrion Street is often used as shorthand for Irish Government in the same way as Whitehall or Downing Street is used to refer to the British government.