21.5258°N, 30.9903°E.
Middle Kingdom Egyptian fortress on a long island in the Nile at the second cataract in northern Sudan, constructed of mud-brick on a stone footing during the reign of Senusret III around 1860 BCE. Uronarti Fortress was triangular in plan to fit the contours of the rocky island, with walls reaching roughly 8 metres in height and equipped with rounded bastions overlooking the river. It functioned as part of the fortified frontier system anchored by Semna and Kumma upstream and Buhen downstream, controlling river traffic and Nubian gold shipments. George Reisner excavated the site for the Harvard-Boston expedition in 1924 and recovered an extensive archive of clay sealings recording the names of officials and the contents of containers passing through. Renewed survey by Laurel Bestock of Brown University began in 2012, focusing on portions above the modern lake level.
The fortress's lower town has been underwater since 1964, but the upper bastions still emerge from Lake Nubia at low pool.