The Medway River in England is 70 miles and the Medway Navigation is 19 miles with ten active locks and one demolished lock.
The River Medway is a river in South East England. The stretch from Leigh to Allington is known as the Medway Navigation, and is 19 miles (31 km) in length. It rises in the High Weald, Sussex and flows through Tonbridge, Maidstone and the Medway conurbation in Kent, before emptying into the Thames Estuary near Sheerness, a total distance of 70 miles (113 km). There are eleven locks on the river. 
