Sawbridgeworth Marsh is a 6.3-hectare (16-acre) biological Site of Special Scientific Interest (SSSI) near Sawbridgeworth in Hertfordshire, apart from a small area in the north which is in Essex.

[1][2][3][a] The site is a river valley marsh close to the River Stort, which has a varied wetland flora.

Grazing and cutting of the marsh in rotation maintain biological diversity.

The site also has an important wetland fauna and many moth species.

[3] The site is always open and there is access from Hallingbury Road.