Milton Keynes ( KEENZ (locally abbreviated to MK) is a large town in (ceremonial) Buckinghamshire, England, about 50 mi north-west of London. It is the principal settlement of the Borough of Milton Keynes, a unitary authority. At the 2011 Census, its population was almost ; the Office for National Statistics estimates that it will reach 300,000 by 2025. The River Great Ouse forms its northern boundary; a tributary, the River Ouzel, meanders through its linear parks and balancing lakes. Approximately 25% of the urban area is parkland or woodland and includes two SSIs.