Cambridgeshire (also known, archaically, as the County of Cambridge; abbreviated Cambs.) is a county in England, bordering Lincolnshire to the north, Norfolk to the northeast, Suffolk to the east, Essex and Hertfordshire to the south, and Bedfordshire and Northamptonshire to the west. The city of Cambridge is the county town. Modern Cambridgeshire was formed on 1 April 1974 as an amalgamation of the counties of Cambridgeshire and Isle of Ely and Huntingdon and Peterborough, which had been created on 1 April 1965 from the historic counties of Cambridgeshire, Huntingdonshire, the Isle of Ely and the Soke of Peterborough. It contains most of the region known as Silicon Fen. Cambridgeshire is twinned with Kreis Viersen in Germany.

Large areas of the county are extremely low-lying and Holme Fen is notable for being the UK's lowest physical point at 2.75 m (9 ft) below sea level. The highest point is in the village of Great Chishill at 146 m (480 ft) above sea level. Other prominent hills are Little Trees Hill and Wandlebury Hill in the Gog Magog Downs, Rivey Hill above Linton, Rowley's Hill and the Madingley Hills.