During the First World War, in spite of its declared neutrality, Iran turned into the scene of battles between Russian and British armies, on the one hand, and Ottomans and Germans, on the other hand. In order to strike a blow to Ottomans, occupy Mesopotamia, and also join the British armies, who were their allies, the Russians began a military campaign in the West of Iran. The Ottomans and Germans also employed certain strategies in opposition to their activities, including providing financial support for Gholamreza Khan, the ruler of Poshtkuh. However, this ruler changed his position in practice and declared his neutrality. Unlike him, the nomads and ethnic tribes of the region, who saw the threats to their territory, equipped their fighters against the Russians and managed to defeat them in their own realm of power. Based on a study of local proofs and oral history preserved by the members of nomadic and ethnic tribes and through library and field studies, this paper aims to clarify the different dimensions of the history of Poshtkuh and the role of nomadic tribes in preventing the arrival of occupying Russian forces in the region.