The Geshurites bordered upon the Philistines, and lived in the mountainous district which terminates the desert on the northeast (marginal reference). They were a different tribe, or, at least, a different branch of it, from the Geshurites who lived on the northeast border of Bashan, and were Arameans 2 Samuel 15:8. The Gezrites, or Gerzites, may be connected with those who gave their name to Mount Gerizim.
Related Commentaries of 1 Samuel 27:8
1 Samuel 27:8
8 And David and his men went up, and invaded the Geshurites, and the Gezrites,c and the Amalekites: for those nations were of old the inhabitants of the land, as thou goest to Shur, even unto the land of Egypt.