The River Perry is a river in Shropshire, England. It rises near Oswestry and flows south to meet the River Severn above Shrewsbury. Along its 24 miles (39 km) length, its level drops by some 320 feet (95 m). The channel has been heavily engineered, both to enable water mills to be powered by it, and to improve the drainage of the surrounding land. There were at least seven corn mills in the 1880s, and the last one remained operational until 1966. The middle section of the river crosses Baggy Moor, where major improvements were made in 1777 to drain the moor. The scheme was one of the largest to enclose and improve land in North Shropshire, and the quality of the reclaimed land justified the high cost. A section of the river bed was lowered in the 1980s, to continue the process.

The River Severn, at 220 miles (354 km) long, is the longest river in Great Britain. It is also the river with the most voluminous flow of water by far in all of England and Wales, with an average flow rate of 107 m3/s (3,800 cu ft/s) at Apperley, Gloucestershire. It rises in the Cambrian Mountains in mid Wales, at an altitude of 2,001 feet (610 m), on the Plynlimon massif, which lies close to the Ceredigion/Powys border near Llanidloes. The river then flows through Shropshire, Worcestershire and Gloucestershire. The county towns of Shrewsbury, Worcester and Gloucester lie on its course.