River Pinn

The River Pinn is in the historic county of Middlesex, in the western part of Greater London. Its source is in Harrow Weald and its confluence with Frays River makes it a tributary of the River Colne.

The river runs through Pinner, Eastcote and Ruislip: the latter may be a notable rise-lip of land as 17th century maps often have the place name but likely derives from "rush leap" - from the local width of the river. It then runs through Ickenham and on to Uxbridge, where it passes through the former grounds of RAF Uxbridge and Brunel University. The Pinn continues on to Pield Heath and Cowley, passing under the Grand Union canal before joining the Frays River, an anabranch of the Colne, at Yiewsley.

Wikipedia