Charles Ellicott Commentary Daniel 8:2

"And I saw in the vision; now it was so, that when I saw, I was in Shushan the palace, which is in the province of Elam; and I saw in the vision, and I was by the river Ulai." — Daniel 8:2 (ASV)

At Shushan— that is, Susa. At this time (see Records of the Past, vol. 1, p. 71, etc.) Susa was, as Daniel describes it, in the province of Elam; at a later period it became the capital of the Persian empire. Daniel was at Susa only in vision; he was not bodily transported there. The Ulai is the river Eulæus, and is mentioned in connection with Susa in the inscription cited above.