From BiblePortal Wikipedia

Hills [1]

Hills. From the Hebrew, gibeah , meaning a curved round hill . But our translators have also employed the same English word for the very different term, har , which has a much more extended sense than gibeah , meaning a whole district .

For instance, in  Exodus 24:4, the "hill" is the same which is elsewhere in the same chapter,  Exodus 24:12-13;  Exodus 24:18; etc., and book, consistently and accurately, rendered "mount" and "mountain."

The "country of the hills," in  Deuteronomy 1:7;  Joshua 9:1;  Joshua 10:40;  Joshua 11:16, is the elevated district of Judah, Benjamin and Ephraim, which is correctly called "the mountain," in the earliest descriptions of Palestine,  Numbers 13:29, and in many subsequent passages.