Western Huntingdonshire is a low limestone upland generally about 200 feet (60 metres) in elevation and covered by Oxford Clay. Situated in the catchment basins of the Rivers Nene and Ouse, the county gradually descends eastward and extends into the Fens, an area of reclaimed marshland in the northeast. The clay-covered chalk uplands are generally in pasture or meadow; the more fertile peat soils of the Fens are intensively cultivated for cereals and sugar beets.

In prehistoric times the county, which consisted mostly of dense woods and marshland, was thinly populated. During the Roman occupation the clay uplands were cleared and settled, and towns were established at Godmanchester and Chesterton. Little is known about the settlement of the county by Angles or Saxons during the early Middle Ages, but invading Danes established a headquarters in the town of Huntingdon in the 9th century. During the 10th century the English reconquered the area. Many medieval abbeys (now in ruins) were established within or adjacent to the former marshlands, which were drained and brought under cultivation by the 18th century. Old stone (mostly medieval) bridges still in use attest to the historic importance of the towns of St. Ives, St. Neots, and adjacent Huntingdon and Godmanchester. Oliver Cromwell (Cromwell, Oliver) spent his childhood in the town of Huntingdon. During the English Civil Wars the town and surrounding countryside nevertheless remained steadfastly Royalist. Huntingdonshire has been primarily an agricultural area for most of its history.

The town (parish) of Yaxley, atop thick Oxford Clay deposits in the north, is now one of the principal brick-making centres of England. Huntingdon, Godmanchester, St. Ives, and St. Neots have expanding light industries. Huntingdon is the administrative centre and county town (seat). Area administrative district, 351 square miles (910 square km). Pop. (2001) administrative district, 156,950.