[2] The river rises in Swindon, east of the town centre in the Walcot area.

[1] Much of its upper course has been culverted and built over; it can be seen east of the Greenbridge retail park, which it flows through in a northeasterly direction.

It runs to the east of the town through Stratton St Margaret, South Marston and Coleshill, Oxfordshire.

It joins the Thames near Lechlade from the southern bank near the A417 bridge on the reach above Buscot Lock.

Extensive remedial works were carried out to reduce the risk of future flooding.