After unlocking your Island Sanctuary in Final Fantasy XIV, there is a lot of work to do to maximize the potential of this venture. Ranking up is worthwhile since you can earn a good amount of gil through relaxing content. Materials are a large part of what keeps your Island Sanctuary running smoothly, and Island Iron Ore is no exception.
Island Iron Ore is an essential resource used for a wide variety of things on your island, like facility upgrades, personal tools, Mammet-sized tools, and Handicrafts. It's a must to know exactly where to find this vital material.
Where to find Island Iron Ore in FFXIV's Island Sanctuary
The node that holds the much-needed Iron Island Ore is the Rough Black Rock. Like with all other nodes, you'll have to enable "Gathering" mode for your island so you can see and interact with the Rough Black Rock. Since you're looking to extract Island Iron Ore, you must have access to the Islekeep's Bronze Beakaxe.

You can find the Rough Black Rock node in the following areas:
Sunrise Lookout: There is an abundance of nodes in this area. (X: 26.5, Y: 19.6). You can go up and down these slopes and find nine Rough Black Rock nodes, joined with plenty of others to choose from to reset and start the circle over.
Screengrab by Fanbyte via Square Enix True Summit: While Rough Black Rock nodes are not the primary node in this area (X: 25.0, Y: 16.2), enough nodes are nearby to make a full gathering circle without leaving the small area. The True Summit area is a very efficient place to farm if you need both Island Quartz and Island Iron Ore. However, if you're only after the Island Iron Ore, you may want to skip this spot since only three nodes grant iron.
Screengrab by Fanbyte via Square Enix