The river is formed from head springs which rise just below Scrapton near Combe St Nicholas and merge just to the south-west of Wadeford to form the river. It flows for a distance of approximately 14 miles in a northerly direction past Donyatt, Ilminster, Puckington, and Isle Abbotts, before joining the River Parrett just above Hambridge . In its first six miles it falls 250 feet, but then meanders sluggishly, with a fall of only 80 feet, to its confluence with the Parrett. On it's journey from source to mouth it is joined by the tributaries, the River Ding and the Fivehead River with Venner's Water, together with several un-named brooks, which drain the north-east flanks of the Blackdown Hills. On the north-west side the tributaries of the Dowlish Stream with Stretford Water and the Wall Brook drain Windwhistle Hill and Sprays Hill and the hill spur above Whitelackington. Approximately 1 mile before the rivers join with the Parrett it is joined by the Westport Canal.