Switzerland · France · The Doubs Border
The shortest of the Goumois climbs, and my own pick for why it's worth doing: barely any traffic.
Ridden 4 August 2018, described in the ride log as "a quick spin for a few more kms in the legs before going home." My own note on the appeal: "this is a great little climb as the road is too narrow for anything bigger than a van so not a lot of traffic on it in either direction at all times of the day..."
La Goule also marks the border itself — per the route notes on the longer Out and Back Three ride, you can continue past La Goule into France and climb back up the other side into Goumois: a short but brutal extension, "around 20% plus for the whole of the 3 kms."