Aria (or Areia) was always understood to be the area around the Areios River, today Hari Rud in Afghanistan (Arrian, Anabasis IV.6.6). It was bounded to the north by Margiana and Bactria, where the area of the Margos River begins; to the west by the big Carmanian desert; to the south by Drangiana; and to the east by the mighty Paropamisadai mountains. The Areios was the backbone of the region, flowing across the land: Aria corresponds almost exactly to the modern province of Herat, which shows the importance of the river throughout history.
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