From the Wikipedia page :
Uxbridge was a local government district in north west Middlesex, England, from 1849 to 1965, based around the town of Uxbridge.
Uxbridge was one of the first towns in England to adopt the Public Health Act 1848 in 1849 and form a local board of health. Under the Local Government Act 1894 the local board's district was replaced by an urban district.
1955 the urban district council successfully petitioned for a charter of incorporation and became a municipal borough.
The district initially consisted of the parishes of Uxbridge and Hillingdon West. In 1929 it was enlarged by gaining from Uxbridge Rural District the parishes of Cowley, Harefield, Hillingdon East and Ickenham. The parishes were abolished in 1938 in order to create an enlarged Uxbridge parish covering the same area as the district. In 1955 it was incorporated as a borough.
In 1965 the borough was abolished and its former area transferred to Greater London and used to form part of the London Borough of Hillingdon.
See also List of Mayors of Uxbridge