South Yorkshire was created as a metropolitan county in 1974 , by the Local Government Act 1972 , from the southern part of the West Riding of Yorkshire and the former county boroughs of Barnsley , Doncaster , Rotherham and Sheffield . It consists of four metropolitan boroughs : Barnsley , Doncaster , Rotherham , and City of Sheffield . South Yorkshire was created on 1 April 1974 as a result of the Local Government Act 1972 .