The Bedfordshire Historic Environment Archive [HER] includes a number of prehistoric and Roman entries for Upper Caldecote. The HER is now online as part of the Heritage Gateway website.
The earliest evidence for human activity in the civil parish of Northill comes from a Palaeolithic handaxe found at an unspecified date at Caldecote Farm [HER 579]. At this remote epoch the presence of a nearby river (the Ivel) must have rendered it more likely that humans would spend time in what is now Northill than in places much further from any reasonably sized body of moving water.
A barbed and tanged flint arrowhead was found at a site north of Biggleswade Road [HER16206]. This probably dates either to the Neolithic or Bronze Age (flint tools continued to be used throughout the Bronze Age as the raw material was more easily obtained and worked than the copper and tine necessary to make bronze implements).
A series of small curvilinear enclosures, running north-south parallel to and west of the River Ivel, were recorded on aerial photographs. They lie just north of Elmcott Farm close to the border with Biggleswade parish [HER 1814]. The enclosures are considered to be prehistoric in origin.
A series cropmarks south of Upper Caldecote and north of Hill Lane were excavated in 1997 [HER 9093]. An abstract of the findings is quoted by the HER thus: "The Initial phase of excavation at Broom Quarry covered an area of 35 hectares across the northern part of the quarry. The archaeology so far revealed represents the period from the Early Bronze Age (c.1800-1600 BC) through to the Middle Iron Age (c.400-100 BC). The earlier Bronze Age phases show a landscape composed of funerary and boundary features upon which Late Bronze Age and Early Iron Age settlement features increasingly encroached. The dominant feature, an early Bronze Age Barrow, became the focus for a middle-late Bronze Age double-ditched boundary nearly half a kilometre in length, and for contemporary burials and ritual deposits".
"The later settlement activity acknowledges these earlier features, as both boundaries and/or burial places. The eastern half of the barrow ditch was infilled and cremations placed within it, the western half remained to be incorporated into the settlement boundary. At the south-east of the barrow, and as part of the extended boundary were two groups of large circular storage pits, some of which contained deliberately placed deposits of animal bone. These pits, and other elements of the Iron Age settlement, had been preserved beneath a headland road".
"No features of later date were identified beyond a system of Post-Medieval field ditches, which, in the main area of excavation, were aligned on the north-south headland road which bisected the site".
The Viatores, a group dedicated to discovering Roman roads in the modern landscape have identified Hill Lane (which forms the parish boundary between Northill and Old Warden) as being the line of a Roman road from Biggleswade to Old Warden [HER 706]. The line has been traced using parish boundaries and traces of surviving earthworks.
In1885 Roman objects were found at Caldecote include pottery, coins and bronze objects, along with a millstone which was given to in the Museum of Archaeology and Ethnography in Cambridge [HER 454]. Finally, Roman pottery was reported from Upper Caldecote [HER 978], some of it from a pit which may have been the remains of a kiln but this is unclear.