Jamieson, Fausset and Brown on Jeremiah 1:15

15. families--the tribes or clans composing the various kingdoms of Babylon; the specification of these aggravates the picture of calamity (Jr 25:9).

throne at ... gates--the usual place of administering justice. The conquering princes will set up their tribunal there (Jr 39:3, 5; 52:9). Or the reference is to the military pavilion (Jr 43:10) [Maurer].