Oxfordshire or Oxon, county (1991 pop. 553,800), 749 sq mi (1,940 sq km), S central England. The county seat is Oxford. The county comprises five administrative districts: Cherwell, South Oxfordshire, Oxford, Vale of White Horse, and West Oxfordshire. The terrain is generally flat except for a branch of the Chiltern Hills in the southeast. The county is drained by the Thames River (or Isis as it is sometimes locally called) and its affluents, the Windrush, the Evenlode, the Cherwell, and the Thame.
The chief occupation is farming (wheat, barley, and oats), with some dairying and sheep raising. Ironstone and limestone are found. Oxford is the industrial center (automobiles and steel products). In the Middle Ages, Oxfordshire was a part of the Anglo-Saxon kingdom of Mercia. During the English civil war it was a stronghold of royalist resistance. The Univ. of Oxford dates from the 12th cent. Near Woodstock, rich in historical associations, is Blenheim Park.