The historical fortress of Aq-Qalih, a large and little-known structure in the Juvayn Plain of northern Khorasan, is tentatively attributed to the Mongol Ilkhanid period based on limited prior studies. However, extant Ilkhanid -period documents offer no confirmation of its existence. Therefore, the hypothesis of Ilkhanid construction relies solely on archaeological evidence and the dated inscription of the Aq-Qalih Mosque. This research seeks to establish the significance of Aq-Qalih as a midway settlement along Ilkhanid travel routes in northern Khorasan, utilizing historical documents and GIS analysis. Further, by comparing Aq-Qalih’s structure with contemporaneous structures in Mongol-influenced regions of China and Iran, this study assesses the hypothesis of Ilkhanid construction. The findings indicate Aq-Qalih’s strategic location along major Ilkhanid travel routes, with the Ilkhans’ and their successors’ annual visits increasing the likelihood of a midway settlement. Moreover, structural comparisons with Chinese examples like Shangdu, Daidu, and Yingchang, as well as Sultaniyya in Iran, reveal significant similarities, bolstering the hypothesis of Ilkhanid-era construction.