South Northamptonshire was a local government district in Northamptonshire, England, from 1974 to 2021. Its council was based in the town of Towcester, first established as a settlement in Roman Britain. The population of the Local Authority District Council in 2011 was 85,189.The largest town in the district was Brackley, which had a population of 14,000 in 2008, followed by Towcester, which had a population of nearly 10,000.