Aldermaston is in West Berkshire, about from the Hampshire boundary. The village is south of the A4 road that links the parish with Newbury and Reading. The main road in Aldermaston, The Street, is part of the A340 road and links the village with Pangbourne and Basingstoke. The course of Ermin Street, the Roman road that linked Calleva Atrebatum (Silchester) with Glevum (Gloucester) via Corinium Dobunnorum (Cirencester) runs south of the village, but none of the road survives in the area.