The Bedfordshire Historic Environment Record [HER] details all Romano-British finds and sites known in the county. It is now available on-line as part of the Heritage Gateway website. Whilst there are prehistoric sites in other parts of the parish there have been none yet discovered close to the village itself.
There have been two finds of Roman material in Southill. A quern stone, used for grinding corn into flour [HER 8236] was one of these. Another was an iron implement which seems to have been designed to pick debris from a horse's hoof and fasten its shoes [HER 14772]. The implement was found in association with the bodies of a horse and rider.