Cumnor Hurst, also known as Hurst Hill, is a wooded hill in the neighbourhood of the village of Cumnor, Oxfordshire, England. It lies to the north of Boars Hill. In 1974 it was transferred from Berkshire.
The hill is a landmark on the ridge of Corallian limestone that is topped by Lower Greensand and Kimmeridge Clay. The Kimmeridge Clay provided bricks and tiles, from clay extracted at the Chawley Brick and Tile Works. It was here that fossilised remains of the dinosaur Camptosaurus were found, in 1879-1880. Remains of Plesiosaurs and Ichthyosaurs have also been found.
Cumnor Hurst is a Site of Special Scientific Interest.