South Glamorgan is a preserved county of Wales.
It was originally formed in 1974 under the Local Government Act 1972, as a county council area. It consisted of the county borough of Cardiff along with the southern part of the administrative county of Glamorgan, and also the parish of St Mellons from Monmouthshire.
These areas were divided between two districts: Cardiff and Vale of Glamorgan (this was an unusually low number of districts to be created in a county in the Act: the only other being the Isle of Wight).
South Glamorgan Council was abolished on April 1, 1996, with both district councils becoming unitary authorities. The unitary authorities took in four communities from Mid Glamorgan, with Wick, St Brides Major, and Ewenny going to the Vale of Glamorgan, with Pentyrch and Creigiau becoming part of Cardiff. South Glamorgan continues in existence as a preserved county for purposes such as lieutenancy, and as such includes those four communities.