Thatcham straddles the River Kennet, the Kennet and Avon Canal and the A4. The parish currently covers the town of Thatcham, with its suburbs of Henwick, Dunston Park and Colthrop, and the village of Crookham including Crookham Common and the eastern ranges of the old RAF Greenham Common airfield. The historic parish once also covered Midgham, Cold Ash, Ashmore Green and Greenham. Thatcham Reed Beds, just to the south of the town, is a site of Special Scientific Interest (SSSI).
