Bletchley is a town in the county of Milton Keynes, though until the administrative boundary change in 1995 it was in Buckinghamshire. It is situated south of Milton Keynes itself, though urban growth has joined the two towns together.

The town name is Anglo Saxon and means Blęcca's wood. It was first recorded in manorial rolls in the Twelfth century as Blechelai.

Bletchley is located on the Roman road Watling Street, and was also a major Victorian railway terminus, which led to the huge urban growth in the town in that period. It is also linked to the Midlands via the Grand Union Canal.

Within the parish of Bletchley was historically the hamlet of Water Eaton. In the urban growth of the Victorian period the town also joined up with nearby Fenny Stratford.

Also with the parish is the stately Bletchley Park, which, during the Second World War was home to The Government Code and Cypher School. The famous Enigma code was solved here.