Mid Glamorgan is a ceremonial preserved county of Wales. From 1974 until 1996, it was also an administrative county, with a county council.
Mid Glamorgan was formed in 1974 under the Local Government Act 1972. It consisted of part of the former administrative county of Glamorgan, and the county borough of Merthyr Tydfil, along with the parishes of Penderyn and Vaynor from Brecknockshire and the urban districts of Bedwas and Machen, Rhymney and part of Bedwellty, from Monmouthshire.
It was divided into six districts:
- Cynon Valley
- Merthyr Tydfil
- Rhymney Valley
Mid Glamorgan's administrative role was abolished in 1996 and split into the unitary authorities of Bridgend, Merthyr Tydfil, Rhondda Cynon Taff and part of Caerphilly by virtue of the Local Government (Wales) Act 1994.
The communities of Wick, St Brides Major, Ewenny became part of the Vale of Glamorgan county borough, with Pentyrch being added to the Cardiff unitary authority area. Because of this, they became part of the preserved county of South Glamorgan. In 2003 the ceremonial borders were further adjusted, placing the entire of Caerphilly county borough in the ceremonial Gwent.