The River Barle runs from the Chains on northern Exmoor, in Somerset, England to join the River Exe at Exebridge, Devon. The river and the Barle Valley are both designated as biological Site of Special Scientific Interest.
On the Chains above Simonsbath is a 3-acre (1.2-hectare) reservoir known as Pinkery Pond. It was formed in the 19th century when John Knight and his son dammed the river at that point. The pond's purpose is unknown, but vestiges of a small canal can be seen nearby. Wheal Eliza Mine was an unsuccessful copper and iron mine on the river near Simonsbath.
The river passes under a late medieval six-arch stone Landacre Bridge in Withypool, and the Tarr Steps a prehistoric clapper bridge possibly dating from 1000 BC. The stone slabs weigh up to 5 tons apiece. According to local legend, they were placed by the devil to win a bet. The bridge is 180 feet (55 m) long and has 17 spans. It has been designated by English Heritage as a grade I listed building. In Dulverton the river is crossed by the Barle Bridge.
The river flows through the Somerset Wildlife Trust's Mounsey Wood Nature Reserve and Knaplock and North Barton SSSI, first notified in 1954, which are within Exmoor National Park. This is notable for the presence of rare plant and bird life and including Kingfisher habitats and one of the only sites of great burnet (Sanguisorba officinalis) on Exmoor. The river itself has been recorded as a habitat for otters.