The Chalk Formation of Southern England is a system of chalk downland in the south of England. The formation is perhaps best known for Salisbury Plain, the location of Stonehenge, the Isle of Wight, and the twin ridgeways of the North Downs and South Downs.
The North Downs are confined chiefly to the counties of Kent and Surrey, and the South to Sussex. Each forms a well-defined long range springing from the chalk area of Dorset and Hampshire, to which, though broken up into a great number of short ranges and groups of hills, the general name of the Western Downs is given. The Downs enclose the rich district of the Weald, where the chalk has eroded to form a much flatter landscape.
In Wiltshire is Salisbury Plain, the Wiltshire Downs, and Cranborne Chase, all three famous for their archaeology, and it was on these downs that Augustus Pitt Rivers developed the methods of modern archaeological field work in the 19th century. The Berkshire Downs and White Horse Hills adjoin the northernmost part of this formation. The formation called Cranborne Chase (grid reference ST970180) is a chalk plateau in central southern England, straddling the counties Dorset, Hampshire and Wiltshire.