Harwell is a village and civil parish in the Vale of White Horse about 2 miles west of Didcot, 6 miles east of Wantage and 13 miles south of Oxford, England. The parish measures about 3.5 miles north – south, and almost 2 miles east – west at its widest point. In 1923 its area was 2,521 acres. Historically in Berkshire, it has been administered as part of Oxfordshire since the 1974 boundary changes. The parish includes part of Harwell Science and Innovation Campus in the southwest.