Iran with its unique geographically most suitable for animal husbandry and has always been a home for myriad of tribes who have played a significant role in its socio-political history. Milan, among the many, is one of the largest nomadic Kurdish tribes in West Azarbaijan province, about which no information except for few is available. Applying qualitative method and semi-in-depth structural interviews and reviewing historical documents, we examined the historical roots of Milan and its socio-economic life in Iran. The findings show that Milan is originally a large Kurdish confederacy in northern parts of Iraq that was forced to move to Turkish borders with Iran during the Ottoman period to counter the Safavid regime's attacks. Due to fertility of lands, Milan resided there forever and then after, some branches migrated to Iran and settled down in its northwestern parts.