Mixbury is a small village in the north-east of the county close to the Buckinghamshire border.
The village mainly comprises two rows of brick-faced semi-detached estate cottages which are laid out as a model village along the road leading south from the church. At one time Mixbury consisted of thatch-roofed rubblestone cottages and was closer to the stream which runs to the north of the village and east of the church. These cottages became dilapidated and were demolished by order of the Court.
The parish church is All Saints' Church which dates from the 12th century. Early in the 14th century all the windows were replaced with Decorated Gothic ones. A south aisle of three bays and a west tower were added at the same time. The Perpendicular Gothic clerestorey was added later.
By the entrance to the church is a restored preaching cross.
Near the church are the earthworks of Beaumont Castle, a Norman possible motte and bailey or ringwork castle. The castle was probably called Beaumont because it occupied a natural promontory overlooking a local stream. The castle was abandoned before 1216. The earthworks are on private land and there is no public access.
Near the viallage is Barrow Hill, where human remains were found in the 19th century.
The parish is notable for its connexion with medieval tournaments, since in 1194 the open ground between Brackley and Mixbury was made one of the five licensed tournament grounds in England.
Mixbury is about two and a half miles south-east of Brackley.