[1] It rises on the eastern side of Black Down[2] at an altitude of 90 metres (300 ft)[3] beneath an artificial lake at Bridehead House, Littlebredy on the escarpment of the Dorset Downs.

It empties into the English Channel over the western end of Chesil Beach where it "forms itself into a pool and fights to get to the sea intact before sinking into the shingle.

The National Landscape Partnership describe it as a broad clay valley having a sweeping profile enclosed by the chalk escarpment to the north and east, and smaller limestone escarpment to the south, with a "strong undeveloped rural character".

[2] Land use is primarily a patchwork of dairy pasture and wet woodland in the valley floor, and arable, scrub and calcareous grassland on the valley sides.

The river gives its name to Long Bredy, Littlebredy, Burton Bradstock and probably Bridport.