Plynlimon (anglicised from Pumlumon in Welsh, meaning "five peaks") is the highest point of the Cambrian Mountains in Wales. It is a massif that dominates the countryside of Ceredigion, Mid Wales.
The highest point of the massif itself is Pen Pumlumon Fawr at 752 metres. Its other important peaks are Pen Pumlumon Arwystli and Y Garn.
The longest river in Britain, the River Severn, has its source on the mountain, as do the rivers Wye and Rheidol.
Folklore says there is a sleeping giant in Plynlimon.