John Gill Commentary Joshua 13:12

"all the kingdom of Og in Bashan, who reigned in Ashtaroth and in Edrei (the same was left of the remnant of the Rephaim); for these did Moses smite, and drove them out." — Joshua 13:12 (ASV)

All the kingdom of Og in Bashan, who reigned in Ashtaroth and
in Edrei (See Gill on Joshua 12:4);

who remained of the remnant of the giants ;
was descended from those that remained in Ashtaroth, after the rest were cut off by Chedorlaomer, (Genesis 14:5) ; called there the Rephaim, as here:

for these did Moses smite, and cast them out :
that is, not only the giants, but the inhabitants of the above kingdom, the greatest part of them; for the Geshurites and the Maachathites are excepted in (Joshua 13:13) .