In the late 1960s, Cardiff Council decided to create low cost social housing in Llanederyn, with an estimated 3,500 homes to be erected for 12,000 less well off people (2000 homes owned by the city council and 1500 private homes).
The district was formed by the Local Government Act 1972, from the county borough of Cardiff, the parishes of Lisvane, Llanedeyrn, Radyr, St. Fagans and Tongwynlais from the Cardiff rural district in the administrative county of Glamorgan and the parish of St Mellons from the Magor and St Mellons Rural District in the administrative county of Monmouthshire.