Regio Patalis is Latin for “the region of Patala”, that is the region around the ancient city of Patala at the mouth of the Indus River in Sindh, Pakistan. The historians of Alexander the Great state that the Indus parted into two branches at the city of Patala before reaching the sea, and the island thus formed was called Patalene, the district of Patala. Alexander constructed a harbour at Patala.