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.