The River Gowy is a river in Cheshire, England and a tributary of the River Mersey. It rises in western Cheshire in the hills near Peckforton Castle, very close to the source of the River Weaver. While the Weaver flows south initially, the Gowy flows north and for several miles provides the valley used by the Shropshire Union Canal. It runs just to the east of Chester and passes through a syphon under the Manchester Ship Canal to meet the Mersey near Stanlow. Its total length is around 20 miles (32 km).