Seventy years - The duration of the Babylonian empire was really a little short of this period. But the 70 years are usually calculated down to the time when the Jews were permitted to return to their country (compare Jeremiah 29:10).
Related Commentaries of Jeremiah 25:11
Jeremiah 25:11
11 And this whole land shall be a desolation, and an astonishment; and these nations shall serve the king of Babylon seventy years.