Thorley Wash or Thorley Flood Pound is a 17.3 hectare biological Site of Special Scientific Interest in Thorley, south of Bishop's Stortford in Hertfordshire. It was formerly a flood pound for the Stort Navigation, which was decommissioned in 2004 and converted to a more natural state. It was purchased by the Herts and Middlesex Wildlife Trust from the Environment Agency in 2011.
Herts and Middlesex Wildlife Trust did not own Thorley Wash in 2003.