Iron Isle is an island that appears in Dragons: Race to the Edge. It is the only known home of the Armorwing.
This looks like an ordinary island, but looks can be deceiving. This island is home to the fearsome Armorwing, a dragon that steals any metal it can find from unsuspecting travelers and fuses it to its hard shell. If you explore this island, make sure your keep a firm hand on your axe or sword.
After Snotlout is given the Jorgenson Ceremonial Axe by his father and entrusted to chop down a tree at a union between House Jorgenson and House Hofferson, he loses it while flying due to his ego and it lands on Iron Isle. Snotlout, Hiccup, and Astrid go down to retrieve it, only to find that it is stuck to the back of an Armorwing. After failing to remove it, Snotlout comes up with a plan to go to Breakneck Bog to lure some Smothering Smokebreaths to Iron Isle, so that they can remove that axe from the Armorwing's back. The plan works at first, but then the teens realize that they're hurting the Armorwing, as it needs to metal for defense as it has no scales on the parts on his body that had the metal, and Snotlout attempts to steal the axe back from the Smothering Smokebreaths, but barely succeeds. The teens then lure the Smothering Smokebreaths away from the Armorwing with a ball of metal they welded together, and the Smothering Smokebreaths fly back to Breakneck Bog. The Armorwing lies on the ground defeated, with his metal armor mostly gone. Suddenly, Toothless and Stormfly bring the Armorwing more metal, and the Armorwing welds it to himself. Hiccup then decides they leave, just in case the Armorwing is still angry and to make the ceremony in time.