Sala is a municipality in central Sweden, in the county of Västmanland. The municipality covers an area of 1172.6 km². Of the total population of 21548, 10697 are male, and 10851 are female. The population density of the community is 18 inhabitants per km².
... all of which were at the far end of the Metropolitan Line, and stretch the definition of "tube station" a little:
Waddesdon tube station[?]
Quainton Road tube ...