How to Get Iron in Animal Crossing New Horizons
By Andrew Lin

How to get iron in Animal Crossing: New Horizons is extremely important to know to progress through the game.
Animal Crossing New Horizons Iron Nuggets
You'll need Iron Nuggets to upgrade your tools, and you'll need 30 of them to unlock the Shop at Nook's. To get Iron Nuggets, you have to hit rocks with an axe or shovel.
Getaway Guide ⑤ - Part 3
— Tom Nook (@animalcrossing) March 6, 2020
Resident Services is also where you'll find the Nook Stop, a terminal with a variety of services, such as a shopping catalog and an automatic Bell dispenser...that's ABD for short. There's also a recycle box for dropping off things you don't need! pic.twitter.com/np3xJwkZt2
Like money rocks from previous games, each rock can dispense up to nine drops. Those drops can be either stones, Iron Nuggets, or the rare Gold Nuggets. To maximize your drops, dig a line of holes behind you so you don't get pushed back as you strike the rock.
Each rock in town can be hit, so if you run out you can head over to another island with a Nook Miles Ticket to harvest.
Once you can buy the Pretty Good Tools guide with Nook Miles, you'll need Iron Nuggets to upgrade flimsy tools to their regular, standard versions. You also need Iron Nuggets to craft your own workbench.