Cambridgeshire is noted as the site of Flag Fen in Fengate, one of the earliest-known Neolithic permanent settlements in the United Kingdom, compared in importance to Balbridie in Aberdeen, Scotland. A great quantity of archaeological finds from the Stone Age, the Bronze Age and the Iron Age were made in East Cambridgeshire. Most items were found in Isleham.
Cambridgeshire was recorded in the Domesday Book as "Grantbridgeshire" (or rather Grentebrigescire) (related to the river Granta).
Covering a large part of East Anglia, Cambridgeshire today is the result of several local government unifications. In 1888 when county councils were introduced, separate councils were set up, following the traditional division of Cambridgeshire, for
- the area in the south around Cambridge, and
- the liberty of the Isle of Ely.
In 1965, these two administrative counties were merged to form Cambridgeshire and the Isle of Ely.
Under the Local Government Act 1972 this merged with the county to the west, Huntingdon and Peterborough, which had been formed in 1965, by the merger of Huntingdonshire with the Soke of Peterborough (the latter previously a part of Northamptonshire with its own county council). The resulting county was called simply Cambridgeshire.
Since 1998, the City of Peterborough has been a separately administered area, as a unitary authority. It is associated with Cambridgeshire for ceremonial purposes such as Lieutenancy, and joint functions such as policing and the fire service.
In 2002, the conservation charity Plantlife unofficially designated Cambridgeshire's county flower as the Pasqueflower.
The Cambridgeshire Regiment (or Fen Tigers), the county-based army unit, fought in the Boer War of South Africa, the First World War and Second World War.
Due to the county's flat terrain and proximity to the continent, during the Second World War the military built many airfields here for RAF Bomber Command, RAF Fighter Command, and the allied USAAF. In recognition of this collaboration, the Cambridge American Cemetery and Memorial is located in Madingley. It is the only WWII burial ground in England for American servicemen who died during that event.
Most English counties have nicknames for their people, such as a "Tyke" from Yorkshire and a "Yellowbelly" from Lincolnshire. The traditional nicknames for people from Cambridgeshire are "Cambridgeshire Camel" or "Cambridgeshire Crane", referring to the wildfowl that were once abundant in the fens. The term "Fenners" was often applied to those who come from the flat country to the north of Cambridge. Since the late 20th century, this term is considered to be derogatory and has been discouraged in use.
Original historical documents relating to Cambridgeshire are held by Cambridgeshire Archives and Local Studies.