Chiltern Hills AONB

The Chiltern Hills or, as they are known locally and historically, the Chilterns, is a range of hills northwest of London. They form a chalk escarpment across Oxfordshire, Buckinghamshire, Hertfordshire, and Bedfordshire.[1] A large portion of the hills was designated officially as an Area of Outstanding Natural Beauty in 1965.

The Chilterns cover an area of 322 square miles (830 km2) stretching 45 miles (72 km) in a southwest to a northeast diagonal from Goring-on-Thames, Oxfordshire to Hitchin, Hertfordshire. At their widest, they are 12 miles (19 km).[2]

The northwest boundary of the hills is clearly defined by the escarpment. The dip slope is by definition more gradual, and merges with the landscape to the southeast.[3] The southwest endpoint is the River Thames. The hills decline slowly in prominence in northeast Bedfordshire.[4]

GeoHopper