Which London Underground line has the network’s highest station, at Amersham?

The Metropolitan line has the London Underground’s highest station, Amersham.

Amersham stands about 150 metres above sea level in Buckinghamshire, making it the highest station on the Underground network. The Metropolitan line reaches Amersham from central London through the north-western suburbs and countryside.

The station opened in 1892 when the Metropolitan Railway extended its route beyond Chalfont Road. Amersham later became one of the line’s outer termini and is also served by Chiltern Railways.

This fact is sometimes confused with the Underground’s deepest station, which concerns the vertical position of platforms below ground. Amersham’s distinction concerns elevation above sea level, not underground depth.