Hywel Dda Local Health Board (Welsh: Bwrdd Iechyd Lleol Hywel Dda), properly Hywel Dda University Health Board, is a local health board in Wales which was established on 1 October 2009 from the merger of the Hywel Dda NHS Trust, the Pembrokeshire Local Health Board, Ceredigion Local Health Board and Carmarthenshire Local Health Board. The local health board is named in honour of historic south west Wales king Hywel Dda.