 Watford became an urban district under the Local Government Act 1894 and a municipal borough by grant of a charter in 1922.The borough, which had 90,301 inhabitants at the time of the 2011 census, is separated from Greater London to the south by the parish of Watford Rural in the Three Rivers District.Watford Borough Council is the local authority with the Mayor of Watford as its head – one of only 18 directly elected mayors in England and Wales.