The seat began with the market towns Uxbridge and Staines shedding the latter and its southern half in 1918; by 1945 more new seats were needed. Its eastern area merited Southall and the loss of Northolt to Ealing West (all new seats) and in 1950 of Ruislip, Northwood and Harefield to become Ruislip-Northwood and of Hayes and Harlington, taking up eastern territory and some of that lost in 1918. In each possible boundary reform the seat was reduced reflecting population expansion of areas outlying its core area of Uxbridge and interwoven Hillingdon, Cowley and Ickenham.
The parishes (as various successor urban districts) marked * were absorbed into Surrey and the others absorbed into Greater London, in 1965.
1918–1945: Uxbridge was cut down to a north-western division of Middlesex. Large areas to the south were removed to form Spelthorne (UK Parliament constituency).
1945–1950: included in 1945's interim redistribution of seats with more than 100,000 registered electors. Reduced to the urban districts of Ruislip-Northwood and Uxbridge. This saw contributions to two new seats: Southall, almost its whole; Ealing West, (as to Northolt); a cast-off for five years to Spelthorne of southerly Yiewsley and West Drayton Urban District.
1950–1974: Under 1950 redistribution, Ruislip-Northwood became a new seat in the north and north-east. Uxbridge with immediate neighbours north south and east (together forming the Municipal Borough of Uxbridge in 1955) was re-united with Yiewsley and West Drayton, to form the last incarnation of the county division.
1965 saw the last major Local Government reform. The area covered became part of the London Borough of Hillingdon.
1974–1983: The seat was reclassified as a borough constituency. Its wards were Colham-Cowley, Harefield, Hillingdon East, Hillingdon West, Ickenham, Uxbridge, and Yiewsley.
1983–1997: ward names were changed to: Colham, Cowley, Harefield, Hillingdon East, Hillingdon North, Hillingdon West, Ickenham, Uxbridge North, Uxbridge South, West Drayton, and Yiewsley. Their coverage remained unchanged.
1997–2010: Harefield ward was transferred to Ruislip-Northwood.
^The seat span approximately 18.5 miles from the north of Harefield on the Hertfordshire border to the Surrey border at Hampton Court Park and 9 miles from the west of Staines to the east of Teddington. Its final form had a greatest ambit of approximately 5.0 miles from north Ickenham to south West Drayton and 3.0 miles east-to-west.