Walland Marsh is a part of Romney Marsh, mostly in Kent with part in East Sussex. The name means wall-land: its north-eastern border, separating it from the rest of Romney Marsh, is the Rhee Wall. The Rhee Wall is 7.5 miles long and runs from Appledore, through Brenzett and Old Romney to New Romney; it consists of two parallel earth banks, from 50 to 100 metres apart, the ground between being raised above the marsh on either side. It was built in the 13th century, as a watercourse to wash away silt from the harbour at New Romney. The plan eventually failed; the Rhee Wall has not contained water since medieval times.