Since I see a lot more hanging at that mountain ridge and did not know myself how to get "back on the map" and finally visit our lovely slum at Nova Tismirr - thanks Muki and a friendly bump so others may see this simple solution!
In detail: switch view to EU map, find yourself (probably stuck at some moutain or river, walk a bit south or north so that no obstacle is between you and the edge of the map any more. Then switch back to NA view, and move to a place on roughly the same height - once you are back on the "right" map, continue as usual...