Plasnewydd is an electoral ward of Cardiff, Wales. It falls within the parliamentary constituency of Cardiff Central. It is bounded by the electoral wards of Cyncoed to the north; Penylan to the northeast; Adamsdown to the southwest; and Cathays to the west. It covers what is now the community of Roath.

Cyncoed ; is a community in the northeast of Cardiff, the capital of Wales. With many properties in the area fetching over £1 million, Cyncoed is considered to have some of the highest property prices in the country. Cyncoed overlooks the city centre of Cardiff, near Roath Park, with views of the surrounding mountains.