Thatcham is a market town and civil parish in the West Berkshire, England. It is situated in the valley of the River Kennet 3 miles (4.8 km) east of Newbury, 14 miles (23 km) west of Reading and 54 miles (87 km) west of London. The town has a long history dating back to prehistoric times, a claimant to the title of oldest continuously inhabited place in Great Britain. As of 2021, it had a population of 25,464, though it is part of a built-up area comprising itself and neighbouring Newbury of over 70,000 residents. It is on the route of the A4 Bath Road, the historic main road between London and Bristol.

West Berkshire is a unitary authority area in the ceremonial county of Berkshire, England. It is administered from Newbury by West Berkshire Council.