The City of Milton Keynes is a borough in Buckinghamshire, England. The borough was created in 1974 and is named after its main settlement, Milton Keynes, which had been designated as a new town seven years earlier in 1967. It is the northernmost district of the South East England Region. The borough abuts Bedfordshire, Northamptonshire and the remainder of Buckinghamshire. The borough was awarded city status in 2022. It is administered by Milton Keynes City Council, which has been a unitary authority since 1997.
The principal built-up area in the borough is the Milton Keynes urban area, which accounts for about 20% of its area and 90% of its population. The borough also includes many rural areas surrounding the Milton Keynes urban area, especially to the north, containing several villages and the town of Olney. At the 2021 census, the population of the borough was just over 287,000.