Lewes Brooks is a 330.07 hectare (822.8 acre) biological Site of Special Scientific Interest in East Sussex, England. The site was notified in 1988 under the Wildlife and Countryside Act 1981. The site is situated to the south of Lewes and west of the River Ouse on a flood plain, and contains many invertebrates, including beetles, snails, and flies. It is the only known UK site for the Lewes water beetle. It is bounded to the south by Rodmell and Southease and to the west by Iford. A lot of mute swans and woodpigeons come here to graze and many songbirds sing in the surrounding hedges. The RSPB also reports that lapwings and snipe have bred here.
Lewes Brooks is where the Falmer-Glynde and the Ouse valleys meet. The Upper and Lower Rises are the remains of the chalk uplands eroded by the Ouse.
There is an RSPB reserve covering much of the area.