Bletchley is a constituent town located within the city of Milton Keynes in Buckinghamshire, England. It serves as the namesake for a larger census "built-up area" situated in the south-west portion of the city.
The Bletchley built-up area is geographically divided by the West Coast Main Line railway. This region encompasses parts of the civil parishes of Bletchley & Fenny Stratford and West Bletchley, as well as a fragment of Stoke Hammond CP. According to the 2021 census, the population of this wider area was 45,010.