The valley of the Lambourn River SSSI from Lambourn to its confluence with the Kennet at Thatcham. It includes the valley of the Winterbourne. At the northern and southern ends, and also through some villages, the area narrows to a buffer along the River.

Joint Character Area: Berkshire and Marlborough Downs

Geology: Largely on the alluvium and river gravels extending onto a few chalk areas at the edge in places, including Boxford Chalk Pit.

Topography: flat riverside land with some gentle slopes at the edge in places.

Biodiversity:

• Chalk river: the River Lambourn is an SSSI and a Special Area for Conservation (SAC).
• Lowland Meadow: there are a number of site between Donnington and Great Shefford including Boxford Water Meadows, Easton Farm Meadow and a number of fields adjacent to Easton Farm Meadow.
• Fen: again the main concentration of sites is between Donnington and Great Shefford. Includes a number of areas in the Kennet and Lambourn Floodplain SSSI which includes Rack Marsh at Bangor.
• Other habitats: The Lambourn and the areas within the Kennet and Lambourn Floodplain are notified as a SAC due to presence of Desmoulin’s Whorl Snail. 

Geodiversity: Boxford Chalk Pit SSSI lies on the edge of the valley.

Access: The main access is along the Lambourn Valley Way footpath.

Targets and opportunties: River management, restoration and protection. Management, restoration and re-creation of lowland meadow, fen and wet grassland habitat especially between Donnington and Great Shefford.