The Bedfordshire Historic Environment Record [HER] contains information on the county’s historic buildings and landscapes and summaries of each entry can now be found online as part of the Heritage Gateway website. The earliest remains of human activity so far found in Thurleigh date to the Neolithic or Old Stone Age. An axe from this period was found in 1941 and is now in Bedford Museum [HER 314].
Thurleigh Castle, dating from the Middle Ages, lay south-east of the church extending as far as the grounds of the Old Vicarage [HER 313]. When the area around the Old Vicarage was developed in the 1970s earlier material, from the Iron Age, Romano-British and Anglo-Saxon periods was found.
A number of sites in Thurleigh date from the Iron Age. This was, as the name suggests, the era when iron-working was first introduced. There have been numerous finds of slag in the parish, which is the waste product from iron working and it is thought that many of these may date from the Iron Age.
Cropmarks are, as the name suggests, features visible in growing crops, areas of disturbance, such as long buried walls or ditches affect the rate of growth of crops and the ghosts of these features can thus be determined from the air by looking at how a crop is growing in a field. North-west of the mill house is an area of cropmarks which are associated with finds of Iron Age pottery and so probably indicate a settlement [HER 2752]. More pottery, from the early Iron Age, has been found south of Park End Farm [HER 2748].