Mythril Island

The Kingdom of Nandorwin settled a city on this island in their initial scouting and colonization of the northern areas of their lands. Before they met the Dwarven kingdom, they had the beginnings of the largest mithril mine in the continent. However, political dynamics shifted drastically within the human kingdom and its government, when they realized that not only was this island essentially in the Dwarves' land, but there were also warrens of tunnels dug by the stout race. It wasn't safe to remain in control of the island, and it would do much to curry favor with a potential ally to hand it over. And so Nandorwin gave up the island, allowing dwarven expertise to further develop the mine, and have the island within their borders in an official sense.