The Royal Military Canal is a canal running for 28 miles (45 km) between Seabrook near Folkestone and Cliff End near Hastings, following the old cliff line bordering Romney Marsh, which was constructed as a defence against the possible invasion of England during the Napoleonic Wars.
The canal is now an important environmental site. The Environment Agency is the navigation authority and uses the waterway to manage water levels on Romney Marsh and Walland Marsh. It is important for fish and other wildlife, including kingfishers, dragonflies and marsh frogs, and it passes through several Sites of Special Scientific Interest. There is now a public footpath for the entire length of the canal via Hythe, West Hythe, Bonnington, Bilsington, Ruckinge, Hamstreet, Warehorne, Kenardington, Appledore, Rye and Winchelsea.