This has been amended and updated many times since it was first passed but it remains the foundational act for principal councils in Wales (and England).
Mae hon wedi cael ei diwygio a’i diweddaru droeon ers iddi gael ei phasio i ddechrau, ond mae’n dal i fod yn ddeddf sylfaenol ar gyfer prif gynghorau yng Nghymru (a Lloegr).