River Pinn

The River Pinn is a suburban river in outer west London. Its source lies in Harrow Weald, and it flows through Pinner, Eastcote, Ruislip, Ickenham and Uxbridge. The river joins the Frays River at Yiewsley, becoming a tributary of the Colne. During the Second World War a small dam near Pinner High Street supplied water for fire-fighting. The middle and lower sections run between the Colne and Crane, flowing south in parallel. The river’s water quality is protected by distant treatment at Mogden Sewage Works. Treated water is discharged to the Tideway, avoiding local contamination. Weak flow is usual except after rain, when worn tyre and motor oil run-off enters the river. Below the A40 trunk road the run-off is particularly hazardous. The Pinn is one of three principal rivers entirely within the historic county of Middlesex. The Celandine Route offers a 19-kilometre walk through woodland, meadows and parks. It ends on the Grand Union Canal towpath beside the Frays River branch of the Colne. A short eastward walk links to the Slough Arm of the canal. The towpath also connects to Brentford, Watford and the Midlands, providing access to central London.