in Susa the capital. In Daniel’s time Susa was the capital of Elam, about 230 miles east of Babylon. It is not clear whether Elam was independent, or aligned with Babylon or Media. Later, however, as one of three royal cities, Susa was the diplomatic and administrative center of the Persian Empire (cf. Neh. 1:1; Esth. 1:2).
the Ulai canal. This canal near Susa connected two rivers that flowed into the Persian Gulf.