Fosdyke Wash is a tidal estuary located in The Wash, a bay on the northwest coast of East Anglia, England. It is a significant habitat for wildlife, particularly birds, and is designated as a Site of Special Scientific Interest (SSSI) and a Special Protection Area (SPA). The estuary is characterized by its mudflats, saltmarsh, and freshwater habitats, which support a wide range of plant and animal species. Fosdyke Wash is also an important stopover point for migratory birds, with thousands of birds visiting the area each year.