The Upper Cam valley is a distinct and separate sub-region, with a readily identifiable topography and history. To the north lies the Western plateau or clay uplands of Cambridgeshire; to the north/northeast are the flat fenlands, each with their own characteristics and patterns of settlement and development.
A cross section of the valley shows the Ashwell tributory of the Cam, known locally as the Rhee, flowing closer to the northern side of the valley, where the land rises quickly to a low chalk elevation, about 60 metres in height. On the broader southern side of the river the low plain is bordered by a series of river terraces which converge with the southern chalk ridge running from east/west, reaching about 150 metres in height. Both chalk ridges are spurs of the Chilterns. The northern spur ends at Chapel Hill at Haslingfield, where one can look down upon Cambridge and the flat lands of the fens to the north of the county. The southern spur continues as a chalk ridge further east into Suffolk and later on Norfolk.
The Upper Cam valley is a low basin, about 10-12 miles long and 4-6 miles wide in places if we include the terraces. The Rhee, which rises at the springs in Ashwell, flows in a northerly direction on the Hertfordshire side of the county boundary and then curves towards the east once in Cambridgeshire. The southern ridge of the valley forms a watershed. All the waters of the River Rhee and its associated streams and ditches flow down to merge with other major tributaries, the Bourne Brook and the Granta, to form the Cam above Cambridge which in turn flows on to join the Ouse and out to The Wash at King’s Lynn.
The Upper Cam valley is quite low lying. The low plain bordering the river is shown below the 15 meter contour line on OS maps. Bordered by porous chalk ridges and underlain with clay soils the valley is therefore prone to flooding. The river itself often floods adjacent land in wet winters – the gentle summer stream becoming a broad expanse. A dense network of small tributory streams, field ditches and drains has been developed and maintained over the centuries, allowing arable farming in the centre of the valley.
There are only a few villages located on the low plain close by the river: Shingay, Wendy and Malton-in-Orwell, all smaller decayed settlements. Most villages are located on the spring line on the broader southern river terraces or on the slopes of the northern chalk ridge, for example Orwell and Haslingfield.
The River Rhee and the parallel ridges, being the most important features, have played a central role in determining patterns of land use and local boundaries. Most parish boundaries are co-terminus with the river and extend back towards the higher ground, giving each parish a classic elongated shape and archetypal mix of water meadow, drier arable land and higher chalk pasture. River and ridge provide the northern and southern limits of parish territorial expansion in the valley. The exception to this is Barrington, which has narrow water meadows on the southern side of the river. Equally streams and drainage courses running into the Rhee are often the eastern and western boundaries, notably in Foxton, Shepreth and Meldreth. Other topographical features forming parish boundaries include ancient tracks, such as the Mare Way which runs along the northern ridge to Chapel Hill above Haslingfield and the Icknield Way, running east-west below the southern chalk ridge. Another ancient route, Ermine Street, a Roman road running due North from Royston across the Upper Cam valley at its widest, forms the boundary between adjacent villages on either side: Wimpole and Arrington, Whaddon and Shingay cum Wendy, Whaddon and Bassingbourn cum Kneesworth.
The prehistoric tracks running east-west provided an important migratory and trading route from East Anglia into the lower Midlands along the southern edge of the Fens (and vice versa). The Icknield Way extends through the Chilterns to link with the Ridgeway, which runs on to the South Coast at Lyme Regis. Eastwards the route links with the Peddlar’s Way running on to the Norfolk coast. So the Upper Cam Valley should also be recognised as a zone of transition between two larger geographical regions.