The region is recognised as a National Character Area (No. 139) by Natural England, the UK Government's advisors on the natural environment. It covers an area of and lies entirely within the Dorset AONB. The boundary of the Marshwood and Powerstock Vales NCA runs along the coastline from just east of Charmouth to West Bay, cutting briefing inland towards Bridport before heading eastwards again to Chilcombe. It then runs broadly north-northeast, taking in Eggardon Hill, before reaching the A356 near Toller Porcorum. It then heads westwards towards Mapperton, Beaminster and Stoke Abbott before swinging in a wide arc to return to the coast via Pilsdon and Whitchurch Canonicorum.