Chiltern Hills

[ chil-tern ]
/ ˈtʃɪl tərn /

noun (used with a plural verb)

a range of chalk hills in Oxford and Buckinghamshire, S England. Highest peak, Coombe Hill, 852 feet (260 meters).
Also called Chil·terns.

British Dictionary definitions for chiltern hills

Chiltern Hills
/ (ˈtʃɪltən) /

pl n

a range of low chalk hills in SE England extending northwards from the Thames valley. Highest point: 260 m (852 ft)