Grid reference TQ854847 Location map Magic Map Area of search Essex | Interest Biological Area 21 km² Notification 1987 | |
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Benfleet and Southend Marshes are a 2077.7 hectare biological Site of Special Scientific Interest (SSSI) on Southend-on-Sea foreshore in Essex. A slightly larger area of 2284 hectares is the Benfleet and Southend Marshes Ramsar site and Special Protection Area. An area of 257.5 hectares in the western part of the SSSI is the Leigh National Nature Reserve (NNR), and this was listed in A Nature Conservation Review as a site of national importance. The SSSI and NNR include the eastern half of Two Tree Island, which is managed by the Essex Wildlife Trust. A large part of the site, 1083.9 hectares, is the Southend on Sea Foreshore Local Nature Reserve.
The site has salt marshes, mudflats, scrub and grassland. The marshes and mudflats have internationally important numbers of wildfowl and waders, including the dark-bellied brent goose, grey plover, redshank and knot. Some areas are very important for scarce invertebrates, such as white-letter hairstreak and marbled white butterflies.