The Marquess of Downshire was recorded in Griiffith's Valuation in 1862 as the landlord of Ballymaconaghy, the townland in which Hillsborough Gardens is located. This was Arthur Hill, 4th Marquess of Downshire. His residence was Hillsborough Castle.
A minute of the Housing Clearance and Redevelopment Committee of 17th of April was tabled requesting this committee's approval of the name Hillsborough Gardens and Ardgowan Drive for new streets on their property at Hillsborough Drive and Ardgowan Street. On the recommendation of the assistant city surveyor, the committee approved thereof (30th April 1963).