River Plym

The Plym at Laira, looking north

The River Plym is a river in Devon which enters the English Channel in Plymouth Sound, before Plymouth, a city which takes its name from the river.

The source of the river is some 1500 feet above sea level on Dartmoor, in an upland marshy area called Plym Head. From the upper reaches which contain antiquities and mining remains the river flows roughly southwest and enters the sea near at Plymouth. The city was historically known as Sutton but renamed in the Middle Ages. Its tidal estuary is known as the Laira (which gives its name to the Laira Bridge over the estuary) is about 20 miles long.

The name Plym is thought to have its origins in Old English and means the 'plum tree', from a back-formation from the name of Plympton.

Miscellany

HMS Plym, a River-class antisubmarine frigate, was named after the river during Second World War. It carried out convoy escort duties in the North Atlantic and was later destroyed in the United Kingdom's first nuclear explosion.

When it was in operation, the Cann Quarry Canal left the river at Marsh Mills.

The Plym Valley Railway is a volunteer run railway which operates steam and diesel hauled train rides along a section of the Plym Valley from Marsh Mills station. The railway is currently extending its line to Plymbridge.