Köseuşağı () is a village in the Çelikhan District, Adıyaman Province, Turkey.Köy , Turkey Civil Administration Departments Inventory. Retrieved 12 January 2023. The village is populated by Kurds of the Reşwan tribe and had a population of 165 in 2021.

The hamlet of Yağmurlu is attached to Köseuşağı.

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