Earl Purple wrote:

I couldn't find a table sorting them but I think this might be the
least used station. (the list doesn't include National Rail stations
that are not also underground ones)

Chesham
Total annual entry + exit (in millions) = 0.407

After looking at likely suspects, I think the four least used stations are
Roding Valley, Chigwell, Grange Hill and Chesham, in that order.