Col du Mont d'Orzeires (el.

), a village in the municipality of L'Abbaye, northeast along lake Brenet, over the Col du Mont d'Orzeires, past Pierre Punex (1061 m a.s.l.)

and continues to Chalêt du Mont d'Orzeires (1029 m a.s.l.

The tunnel was built in response to a petition from the residents of the valleys of 1867[1] and opened in 1886.

[2] It had a dual function, as it was not only serve the railway but, in the case of an extraordinary flood, it could also be used to empty water from the two lakes.