Cyn etholiadau'r Senedd, ysgrifennodd y cyn Weinidog Tai a Llywodraeth Leol at yr Aelodau i'w hysbysu bod tri maes lle gofynnwyd i Gomisiwn Ffiniau a Democratiaeth Leol Cymru, o ganlyniad i'r lefel sylweddol o sylwadau a dderbyniwyd, gyflwyno gwybodaeth ychwanegol. Caerdydd, Sir y Fflint a Chaerffili yw'r ardaloedd hyn.
Before the Senedd elections, the former Minister for Housing and Local Government wrote to Members to inform them that there were three areas where, as a result of the significant level of representations received, the Local Democracy and Boundary Commission for Wales had been asked to submit additional information. These areas are Cardiff, Flintshire, and Caerphilly.