Oxfordshire ( short Oxon , from the Latinised form Oxonia ) is a county in the South East of England , bordering on Northamptonshire , Buckinghamshire , Berkshire , Wiltshire , Gloucestershire , and Warwickshire . Oxfordshire ( or ; archaically the County of Oxford ; abbreviated Oxon from the Latinised form of `` Oxford '' , Oxonia ) is a county in the South East region of England , bordering on Warwickshire , Northamptonshire ( to the north\/northeast ) , Buckinghamshire ( to the east ) , Berkshire ( to the south ) , Wiltshire and Swindon ( to the southwest ) , Gloucestershire ( to the west ) and Warwickshire ( to the north ) .