Rack Marsh is a 4-hectare (9.9-acre) nature reserve in Bagnor, on the north-western outskirts of Newbury in Berkshire.

[1] It is also part of the Kennet and Lambourn Floodplain Special Area of Conservation.

[1] A thick layer of peat has developed on top of the deposits of alluvium and gravel which the river has spread over the chalk.

[5] In 1996 the discovery of the rare Desmoulin's whorl snail on the reserve meant that the Newbury bypass was almost stopped, but the high court ruled in the developers' favour.

[6] The decision to continue with the construction of the road meant that the nature reserve was cut in size, losing half its area.