The Blast Furnace in OSRS sits in Keldagrim. You need to start The Giant Dwarf quest to enter the city.
Here's how to get there:
- Walk from Seers' Village: Go north to Rellekka, then east to the mines. Talk to the Dwarven Boatman to enter Keldagrim.
- Use the mine cart: After your first visit, use mine carts from Dwarven Mines under Ice Mountain or the Grand Exchange.
- Take Fairy Rings: Ring DKR brings you near Grand Exchange and then you have to take mine cart. Ring DKS drops you near Keldagrim entrance.
- Group teleport: If unlocked, teleports you outside the Blast Furnace building.
If you're running low on coins for supplies, consider options to buy OSRS gold to keep your smithing going.
New players sometimes die on the way to Keldagrim. Learn how to get rid of skull OSRS before making the trip if you're worried about PKers in the wilderness areas.