The Rödjorden area covers an area of 1.5 square kilometers. Through numerous surveys, archaeologists have discovered nearly 50 prehistoric iron smelting sites with blast furnaces using red clay as a raw material. The oldest dates back to 700 BC and the most recent to 125 AD. In the 1980s, the Riddarhyttan Photography Club, together with archaeologist Viking Vedberg, carried out a reconstruction of iron smelting near a prehistoric furnace site dating back to around 0 AD.