Dyfed County Council was created on 1 April 1974 under the Local Government Act 1972.

It took over the functions of the three previous county councils which had covered the area: Cardiganshire, Carmarthenshire, and Pembrokeshire.

The vast majority of the councillors elected in 1973 were members of one of the three previous county councils.

At the 1977 election, Plaid Cymru gained some ground although not to the extent that was seen in parts of the South Wales valleys in that year.

[4] Political control of the council from 1974 until its abolition in 1996 was held by the following parties:[5] The council inherited several offices from its three predecessor county councils, including the three former county councils' main offices, being Swyddfa'r Sir in Aberystwyth from Cardiganshire, County Hall, Carmarthen from Carmarthenshire, and the County Offices on St Thomas Green in Haverfordwest from Pembrokeshire.