Silicate slag inclusions in iron artifacts from the Trans-Urals and in iron slags from sites of the Itkul culture were analyzed to assess the geochemical characteristics of iron ore sources exploited during the Early Iron Age. Slag inclusions were found in 19 out of 25 samples from Kichigino I and Krasnaya Gorka. For comparison, we used 12 iron slag samples from Early Iron Age and medieval sites near Lake Irtysh and from Zotino mine. Via statistical analysis, four geochemical groups were separated, each including one or more Kichigino artifacts, which suggests a variety of iron ore sources used by the nomads. Slags and artifacts of the first group are associated with infiltration-sedimentary ironstone ores of the Middle Trans-Urals. Smithing slag from the Itkul site of Shatanov V suggests that these ores were already smelted in the Early Iron Age. The fact that group 1 includes only one artifact from Kichigino I demonstrates that the nomads of the Southern Trans-Urals obtained iron mainly from other sources. Group 2 is characterized by a higher content of Mn and sometimes Ba and S in inclusions. This may attest to the use of Fe-Mn ironstone associated with barite-polymetallic deposits of Central Kazakhstan. Group 3 shows an elevated content of CaO and MgO, indicating the use of ironstone from platform carbonate strata. In the fourth group, the content of K2O is high, and that of MnO, low.