Great Barford has a fair number of Iron Age sites identified through cropmarks and excavation. A number of these also continue, as one would expect, into the following Roman period. The Bedfordshire Historic Environment Record [HER], now on-line on the Heritage Gateway Site has recorded the following sites:

• Work in advance of the Great Barford bypass [A421] in 2005 at a site between Roxton Road and the line of the bypass, north-east of the village found evidence for settlement from the middle Iron Age, preceded by suggestions of activity in the Bronze Age and earlier Iron Age. The site had previously been thought to be purely Romano-British in date. Occupation took the form of roundhouses, pits and enclosures and continued into the late Iron Age [HER 482].
• A trapezoidal enclosure north-west of Birchfield Farm was discovered when the Southern Feeder Gas Pipeline was excavated [HER 1631]. A ditch section was recorded, which produced one sherd of coarse pottery thought to be Iron Age.
• Also discovered when the gas pipeline was excavated was a small rectangular enclosure attached to linear feature north of Cuckoo Bridge [HER 9834]. A number of ditches and possible pits were discovered, although the area was heavily disturbed by land-drains, some of which actually ran through features. Between the main features were traces of smaller features, some of which may have been postholes. It proved impossible to record these because of the conditions prevailing during construction. All the features had fills of clay and gravel, together with large quantities of charcoal. Large quantities of Iron-age pottery (mainly shell tempered) were recovered from these features.
• A site near the village contained evidence for a settlement from the Middle to Late Iron Age [HER 13410]. Within the settlement were two ditched enclosures. One was a rectilinear enclosure with two possible access routes. The second enclosure was of an irregular, curvilinear plan. There was one round house on the site and it was located between the two enclosures. The round house had a small pit in the centre which contained burnt stones and may indicate a hearth. Two gullies on a north-east - south-west alignment stopped just before the house. There was also a single cremation on the site and this was thought to be Roman.
• On the line of the modern A421, just south-west of the junction with Barford Road, a site on a north-east facing slope  was subject to trial trenching [HER 13411]. Two ditches, two pits and a grave were found. The grave is believed to be the earliest feature and contained an adult crouched burial, facing south. It is thought that the grave is of a Late Iron Age or Early Roman period, but this is not certain.
• A site a Birchfield Road, near Birchfield Farm [HER 13497] had extensive evidence for Iron Age and Roman activity. The earliest evidence was for middle Iron Age occupation, in the form of small enclosures and pits. By the late Iron Age a more extensive enclosure system had been constructed. A burial was found to the east of the enclosure in a north - south aligned ditch.
• Excavations occurred to the north of Brewers Hall Farm in 2005, located on a gentle south-west facing slope [HER 15340]. The earliest activity on the site dates to the Iron Age and relates to a single isolated pit. The site was then occupied through the Romano-British period.
• Trial excavations were carried out at a site located 1200 metres to the south-east of Workhouse End near Great Barford on undulating lands that rises to the north and dips to the south towards the River Ouse [HER 15492]. A sequence of occupation from the early Iron Age to the Medieval period was identified, with a peak of activity from the late Iron Age to the Roman period. The Iron Age produced evidence for pits, ditches, of which one was curvilinear, pits, postholes, a water hole, and a metalled surface. The features were dated by the finds evidence of which a large portion was ceramic. A square enclosure, another metalled surface, linear features, pits and post holes were all ascribed a late Iron Age to Roman date.
• Excavations to the north-west of Brewer's Hall Farm uncovered the remains of an Iron Age farm settlement [HER 18224]. The site contained a roundhouse, ditches, pits and postholes, with minor late Iron Age and early medieval components. The first period of activity appears to have occurred in the middle Iron Age and mainly consisted of pits and ditches, which are thought to be associated with a settlement, possibly located to the south. Within the later years of this period the remains of a roundhouse and associated pits were present and were thought to indicate direct occupation of the site. After a short period the roundhouse was removed and the site appears to have reverted back to agricultural use and an enclosure was constructed. During the late Iron Age the enclosure continued in use and a pit was the only new feature. There was limited evidence for late Anglo-Saxon and early Medieval activity on the site in the form of a gully, thought to be associated with an enclosure or a field system of this period.
• HER 18258 Iron Age pottery has been found east of Mill House [HER 18258] on a site occupied in the Roman period [HER 18258].