Castlethorpe is a village and civil parish with a population of about 1000 in the unitary authority area of the City of Milton Keynes, Buckinghamshire, England.

The village is relatively more recent than those around it, and it started out in life as a castle belonging to the lord of the manor of nearby Hanslope.

Although Mauduit returned to claim his seat after the King's death, the castle was demolished shortly afterward.

Multi-dwelling fires in the village have been reported in local media, notably those of 1899 and especially 1905 (when 13 cottages were destroyed, leaving 36 people homeless).

[3] Castlethorpe has grown up around the church and some traditional old stone cottages at the centre of the village which is designated a conservation area.