A waymarked trail through Hafren Forest leads to the source of the River Severn, Britain’s longest river, which rises from a peat bog on the flank of Pumlumon. The source itself is an unshowy spot marked by a simple post, but the walk in through the forestry and up onto the open moor is the reward. Start from the forest car park, and wear boots: the ground gets wet near the top.
Full name: Source of the River Severn (Hafren Forest)
