An archaeological mitigation programme, comprising a strip, map and sample investigation and a formal excavation of identified features, was undertaken by Cotswold Archaeology in August and September 2018. The archaeological mitigation programme was implemented along the proposed route of the new H186 Faringdon to Blunsdon Water Main: Phase 1, which extended across the Oxfordshire/Wiltshire county boundary. A late prehistoric ditch was recorded towards the eastern end of the Phase 1 route. A small number of other, undated features, comprising two further ditches, a curvilinear ditch, a gully and a pit, were also recorded in this area. A number of these appear likely to be of later prehistoric date. A small number of unstratified finds included Roman, medieval and post-medieval pottery. Extensive, plough-degraded evidence of ridge and furrow cultivation, of probable medieval date, was recorded at the western end of the Phase 1 route, and is likely to be associated with known contemporary settlements within the surrounding area.