The central section of three bays, which was projected forward, featured an opening formed by a pair of Ionic order columns supporting an entablature.

[2] In 1821, the Round Room was built in order to receive King George IV,[3] while the stained glass window on the staircase was made by Joshua Clarke and Sons for the visit of Queen Victoria in 1900.

[3] However the decision of the Government to erect a new Department of Industry and Commerce on a site on the same block, on Kildare Street, led to the abandonment of the plans.

[6] In August 2006, the loyalist paramilitary Ulster Volunteer Force claimed they had planted a bomb in the Mansion House in 1981, in an attempt to wipe out the Sinn Féin leadership at their party conference of that year.

[7] The claim led to a security alert at the house, as the Garda Síochána and army searched for a 25-year-old bomb, but none was found.