הַר har "hill, mountain" is a common word used:
in the names of particular "Mounts" (Amos 4:1 & 6:1 - Mount Samaria - in the later case paralleled with "Zion"
of hills in general (4:13 & 9:13)
 
So, in Amos we find at 3:9 "hills of Samaria", some commentators see this as problematic, since elsewhere Amos uses the singular "Mount Samaria" (as the LXX does here) perhaps however the focus is different, all of the hill country of Ephraim not merely the capital city.