Sandy is quite rich in prehistoric and Roman sites and finds. The Bedfordshire Historic Environment Record [HER] lists all the prehistoric, Roman and Anglo-Saxon sites known in the county and is now on-line as part of the Heritage Gateway website.

The HER gives a detailed description of cropmarks just east of Seddington and indicates that they a medieval site [HER 1495], but also: "An area of cropmarks indicating prehistoric activity to the west of the River Ivel. Several ring ditches have been recorded, and one probable oval barrow likely to be of Neolithic date…A small trenching evaluation at the northern end of the site found evidence of substantial Saxo-Norman/medieval boundary ditches". Ring ditches are generally identified as Bronze Age features, the remains of round houses or round barrows.

Cropmarks west of Seddingtonconsist of two semi-circular cropmarks and a small rectilinear feature. These features are probably hut circles and a small enclosure of prehistoric date [HER 13724].  Earthworks south-east of Seddington may represent waterlogged evidence for Late Iron Age and early Roman riverside activities [HER 9835],