Iron in Valheim mainly comes from Scrap Iron mined inside Sunken Crypts in the Swamp. You need to defeat The Elder first to obtain the Swamp Key, then find a crypt, unlock it and break Muddy Scrap Piles with a pickaxe.
Iron in Valheim is a huge progression material because it is used for weapons, armour, tools, building supports and later crafting stations long after you leave the Swamp.
How to get the Swamp Key
Defeat The Elder in the Black Forest. The boss drops the Swamp Key, which opens the locked iron gates on Sunken Crypts.
The key is reusable, so one kill is enough for every crypt in that world.
Where to find Sunken Crypts
Explore large Swamp biomes and look for the green-lit stone entrances with iron gates.
Small Swamps may contain no crypts at all, so sailing to another island can be faster than endlessly searching a tiny patch.
How to mine Scrap Iron
Inside a crypt, use a pickaxe on Muddy Scrap Piles. The piles block corridors and can drop Scrap Iron along with other Swamp loot.
Open chests as well because additional Scrap Iron can appear there.
How to smelt Iron
Take Scrap Iron to a Smelter and add Coal. One processed unit becomes an Iron bar.
Standard wooden portals block Scrap Iron and Iron, so plan a ship, cart route, Stone Portal or portal-world modifier depending on your progression and world settings.
Best pickaxe for iron runs
A Bronze Pickaxe works, while stronger pickaxes improve durability and mining speed.
Bring materials for a Workbench or spare pickaxe if the crypt is far from home, because repairing mid-expedition can save a long trip.
What should you craft first?
An Iron Pickaxe is one of the best early choices because it is needed for later Mountain silver mining.
Iron armour and weapons are strong Swamp upgrades, but avoid spending every bar before considering Longship nails, Stonecutter access and other infrastructure.
Other sources of iron
Later biomes contain additional iron opportunities, including structures and alternative scrap sources, but Sunken Crypts remain the main reliable progression route.
If you need a large amount for building, returning to a crypt-heavy Swamp is often faster than relying on incidental late-game drops.
Best iron farming strategy
Mark every crypt, park a Longship near the coast and use a cart or temporary chest to stage Scrap Iron.
Iron in Valheim remains useful for the entire game, so mining more than the minimum boss requirement is rarely wasted effort.
Iron for building
Iron beams and reinforced structures make large stone builds much easier, which is why builders can consume more Iron than combat players ever expect.
Iron in Valheim is one of the few metals worth massively over-farming because later stations and construction keep asking for it.
Official site: Valheim
