Sudbury (, Suffolk dialect: ) is a small market town in the English county of Suffolk. It is located on the River Stour near the Essex border, and is north-east of London. At the 2011 census, the town has a population of 13,063, rising to 21,971 including the adjoining parish of Great Cornard. It is the largest town of Babergh district council, the local government district, and is represented in the UK Parliament as part of the South Suffolk constituency.