[3] It rises in the Blackdown Hills at a spring near RAF Culmhead in Somerset, and flows west through Hemyock, then Culmstock (in the Culm Valley) to Uffculme.

The Spratford Steam, whose waters have flowed in a southerly direction, meets the Culm near Willand, and thereafter the river shares its valley with the present main railway line (former Great Western Railway) from Taunton to Exeter.

The M5 motorway runs beside the railway, and all three continue past the market town of Cullompton.

Shortly prior to reaching Hele - near Kensham House - the small River Weaver flows into the Culm from the east.

At Perlycombe it is a noisy little brook, at Perlycross, a genial trout stream; while Perliton, by the time it gets there, entitles it "the River Perle" and keeps two boats upon it, which are not always more aground than landsmen should desire.