Mornington is a village and townland in Co. Meath, near the mouth of the River Boyne. However, this street almost certainly derives its name from the peerage title Earl of Mornington. The first holder of this title was Garret Colley Wesley (1735-81), father of Arthur Wellesley, 1st Duke of Wellington. This street is located off Annadale Avenue, whose name is connected with Anne Hill-Trevor, Countess of Mornington and the mother of the Duke of Wellington.
This name is unusual in having no word denoting a street combined with it. Mornington Mews, Mornington Park and Mornington Place are side-streets off Mornington. All of these streets were built in the first decade of the 21st century. Long before this, Mornington Street was built in 1875 off Lower Ormeau Road. It was later cleared for redevelopment. The name is perpetuated by the Mornington Community Project in this area.