Today #Borders takes us to the village of Strömstad (now Sweden) in 1751, when a peaceful treaty between Denmark-Norway and Sweden divided Sweden and Norway to the borders we know today. Unlike the previous treaties discussed so far, this particular treaty was defined by a decade-long mix of investigations and negotiations.
The border was based on knowledge shared among local people, mainly related to which farm belonged to which parish and which parish to which diocese. In the unpopulated mountains the border mainly followed the water divide. There were disagreements on the parishes of Särna, Idre, Lierne, Kautokeino and Karasjok, which had to be solved by give-and-take. Based on that, in 1752–1765 border cairns were erected between Norway and Sweden (including Finland), most of which still remain there today. Since the Sami people lived on the mountains and regularly crossed the border, a second treaty, the Lapp Codicil of 1751, was agreed, giving them the right to freely cross the border with their reindeers.
On Archives Portal Europe you can find the documents detailing the work of the commission to establish these borders.