The river which bordered the eastern Persian Empire was the Indus.
Indus River.
The Indus River.
At its largest extent, the Persian Empire reached the river Indus (in present day Pakistan). This was not always the eastern border as the size of the empire varied. Save
He got as far as the Beaz river.
No
King Darius I extended the Persian Empire into today's Pakistan (west of the Indus River).
The Persian Empire
Amu Darya.
King Darius I.
The Indus River.
The Indus River.
The Tigris River is further east than the Euphrates River.