Wessex Archaeology (WA) was commissioned by Norfolk Vanguard Ltd and Norfolk Boreas Ltd to undertake a programme of geoarchaeological and archaeological monitoring of further engineering-led Site Investigation (SI) works along the route of the Norfolk Vanguard and Norfolk Boreas Onshore Cable Routes (including proposed landfall and substation sites). SI works (cable percussion boreholes, cone penetration tests and trial pits) were undertaken at locations across the onshore project area. The SI works were an engineering-led program involving (geo)archaeological collaboration with the engineers. Where possible, SI interventions were located away from known areas of high archaeological potential. However, the Happisburgh Landfall boreholes are near to Happisburgh 1, an internationally significant Lower Palaeolithic site (Lewis et al. 2019). All Happisburgh Landfall cable percussion boreholes were subject to permanent geoarchaeological monitoring. Possible early Middle Pleistocene (MIS 13; 524-478 Ka) alluvial deposits were identified in two boreholes at the Happisburgh Landfall. These are overlain by Anglian glaciogenic deposits of the Happisburgh Formation (MIS 12; 478-424 Ka) and underlain by likely marine sands of the Wroxham Crag (2.4->0.6 MA). The possible alluvial deposits may be the stratigraphic equivalent to the upper grey sand and organic mud of the Low Lighthouse Member of the Cromer Forest Bed Formation (CF-bF) at Happisburgh 1, which have produced internationally significant Lower Palaeolithic archaeology and paleoenvironmental evidence (Lewis et al. 2019). Intact UT100 and disturbed bulk samples were recovered from the possible alluvial deposits and underlying, likely marine, sands. Stage 3 palaeoenvironmental assessment of samples from the Happisburgh Landfall is recommended. This will enable the presence/absence of CF-bF deposits to be established and their palaeoenvironmental potential to be assessed. Assessment should include samples taken from postulated marine sands of the Wroxham Crag in order to clearly define the stratigraphic separation between marine sands of the Wroxham Crag, and potential alluvial deposits of the CF-bF. Based on the results of the Stage 3 assessment, further targeted geoarchaeological boreholes may be required to map deposits of the CF-bF and to take further palaeoenvironmental samples. Anglian glaciogenic deposits are present across the proposed cable routes. These have generally low geoarchaeological and arc...