It rises on the eastern slopes of Dunkery Beacon and flows north through Timberscombe and Dunster flowing into the Bristol Channel at Dunster Beach.
It has been designated as a Grade I listed building and Scheduled Ancient Monument.
[1] It is a narrow stone packhorse bridge, on the southern outskirts of Dunster, with two arches over the River Avill.
[3] Near to Dunster Beach the stream is crossed by a bridge on the West Somerset Railway.
The river was part of the inspiration for the hymn All Things Bright and Beautiful.