This volume describes the results of a series of archaeological excavations undertaken in advance of the construction of a new dual carriageway, some 32 km long, across Anglesey. Five main sites and a series of prehistoric burnt mounds are discussed. The route encountered remains of Neolithic pit groups and a possible Late Neolithic ring-ditch; Bronze Age and Iron Age settlement features and a Bronze Age cremation cemetery; Romano-British settlements and a farmstead; an early medieval inhumation cemetery, medieval agricultural features and a corn-drying kiln.