The River Sheaf is a river in Sheffield, South Yorkshire, England. Its source is the union of the Totley Brook and the Old Hay Brook in Totley, now a suburb of Sheffield. It flows northwards, past Dore, through the valley called Abbeydale (so named because of Beauchief Abbey, which overlooks it) and north of Heeley. It then passes into a culvert, through which it flows under the centre of Sheffield emerging just once before joining the River Don near Blonk Street Bridge. This lower section of the River Sheaf together with the River Don, between the present Blonk Street and Lady's Bridges, formed two sides of the boundary of Sheffield Castle.