The earliest settlement of Didcot was sited on a wooded ridge arising from the surrounding marshlands. The Romans tried to drain the marshland by digging a ditch still seen today north
of the town near Long Wittenham. The parish church and some houses and streets of the old village still straddle the southern incline of that ridge.
The town of Didcot is located 10 miles south of Oxford. Originally in Berkshire it became the largest town in south Oxfordshire, even though right on its boundary, when transferred to the
district in 1974.