Milton Gate Marsh is a biological Site of Special Scientific Interest north-west of Eastbourne in East Sussex.
This site consists of two areas of alluvial wetland in the valleys of the River Cuckmere and one of its tributaries. There is a rich variety of invertebrates, including seventeen nationally scarce species such as the sallow clearwing moth and the beetles Ochthebius exaratus and Stenolphus skrimshiranus.