Which London Underground line has a branch terminating at Chesham?

The Metropolitan line has a branch terminating at Chesham.

Chesham is the northern terminus of the Underground’s Chesham branch, which runs from Chalfont & Latimer through the Chilterns. The branch became part of the Metropolitan Railway when it opened to Chesham in 1889.

The route is notable because Chesham lies outside Greater London, in Buckinghamshire, and is in fare zone 9. It is also the northernmost station on the London Underground network. Services on the branch connect with the main Metropolitan line at Chalfont & Latimer.

Travellers sometimes confuse Chesham with Amersham, another north-western terminus. Amersham is farther along the main route, while Chesham is reached by a separate branch from Chalfont & Latimer.