In the valley of the River Kennet, south of Oxford, north of Winchester, south east of Swindon and west of Reading. Newbury lies on the edge of the Berkshire Downs; part of the North Wessex Downs Area of outstanding natural beauty, north of the Hampshire-Berkshire county boundary. In the suburban village of Donnington lies the part-ruined Donnington Castle and the surrounding hills are home to some of the country's most famous racehorse training grounds (centred on nearby Lambourn). To the south is a narrower range of hills including Walbury Hill and a few private landscape gardens and mansions such as Highclere Castle. The local economy is inter-related to that of the eastern M4 corridor, which has most of its industrial, logistical and research businesses close to Newbury, mostly around Reading, Bracknell, Maidenhead and Slough.