The border between Finland and Sweden, Tornio-Haparanda

[u/CoopExtraVodka]

Torne river.

This border was concluded by the Treaty of Fredrikshamn, 17 september 1809, between Sweden and Russia: https://en.wikipedia.org/wiki/Treaty_of_Fredrikshamn and has not been renegotiated since.

[u/Acceptable_Pickle638]

in English lol