CHILTERN HILLS or THE CHILTERNS, a range of chalk hills in England, extending from south-west to north-east through part of Oxfordshire, Buckinghamshire and Bedfordshire. They form a well-marked escarpment, facing north-westwards, with a long south-eastern slope, and run from the Thames in the neighbourhood of Goring to the headwaters of its tributary the Lea between Dunstable and Hitchin, the crest line between these points being about 55 miles. But these hills are part of a larger chalk system, continuing the line of the White Horse hills from Berkshire, and themselves continued eastward by the East Anglian ridge, a series which represents the edge of the chalk rising from beneath the Eocene deposits of the London basin. The greatest elevation of the Chilterns is found in the centre from Watlington to Tring, where heights from Boo to 85oft. are frequent. West ward towards the Thames gap the elevation falls away but little. but eastward the East Anglian ridge does not often exceed 5oof t. There are several passes through the Chilterns, followed by main roads and railways converging on London. The hills were for merly covered with beech, and there is still a local supply of this wood for the manufacture of chairs and other articles in the neighbourhood of Wycombe.