Mount Ephraim is referred to over 30 times in the King James Version. Mount Ephraim is not a specific mountain but is the hilly or mountainous region of Ephraim’s territory. Although people normally think of a mountain as bigger than a hill, there is no specific criterion that separates the two. Hill and mountain are relative terms and can be used interchangeably when referring to some of the geography of the area.
Most modern translations use the term hill country of Ephraim or occasionally the mountains of Ephraim. Even the King James Version demonstrates that Mount Ephraim is not a single mountain and is rather a mountainous or hilly region: “And Abijah stood up upon mount Zemaraim, which is in mount Ephraim, and said, Hear me, thou Jeroboam, and all Israel” (2 Chronicles 13:4). For Mount Ephraim to be a single mountain, one would have to imagine Mount Zemaraim being in or on Mount Ephraim. Likewise, for 2 Chronicles 15:8 to be coherent, one would have to imagine a single mountain with several cities on it: “And when Asa heard these words, and the prophecy of Oded the prophet, he took courage, and put away the abominable idols out of all the land of Judah and Benjamin, and out of the cities which he had taken from mount Ephraim, and renewed the altar of the Lord, that was before the porch of the Lord.”
About half the territory occupied by the tribe of Ephraim was hilly or mountainous, and the other half was flatter, approaching the coastal plains. In Joshua 19:50, Joshua, who was of the tribe of Ephraim, received a city in the hill country of Ephraim as his inheritance. Later, he was buried there (Joshua 24:33), as was Eleazer the high priest, son of Aaron (Joshua 24:33). Shechem, a city of refuge, was also located in the hill country of Ephraim or “Mount Ephraim” (Joshua 21:21).
In Judges, much of the action takes place in the hill country of Ephraim. Ehud (a Benjamite) rallied the people for battle in the hill country of Ephraim, which bordered the territory of Benjamin (Judges 3:27). Deborah, of the tribe of Ephraim, lived in the hill country (Judges 4:5). Gideon later rallied troops from the mountains of Ephraim (Judges 7:24). Abimelech, a lesser-known judge, lived there, too (Judges 10:1). The sad tale of Judges 18—19 is set in the same area of Mount Ephraim.
Saul searched for his missing donkeys in the hill country of Ephraim (1 Samuel 9:4), and some men of Israel hid from the Philistines there (1 Samuel 14:22). Sheba, one of the men who sided with Absalom against King David, is also listed as being from the hill country (2 Samuel 20:21).
After Israel split into northern (Israel) and southern (Judah) kingdoms, Ephraim was on the southern border of the northern kingdom. King Jeroboam built the city of Shechem in the hill country as one of his royal residences (1 Kings 12:25). Since it was on the border between the northern and southern kingdoms, some of the territory passed back and forth, as in 2 Chronicles 15:8.
In Jeremiah 4:15, Dan and “mount Ephraim” are mentioned because they represent the northernmost and southernmost boundaries of the northern kingdom of Israel: “A voice is announcing from Dan, proclaiming disaster from the hills of Ephraim.” In other words, judgment is coming on the land “from top to bottom.” However, Jeremiah also promises that the Lord will redeem His people: “There will be a day when watchmen cry out on the hills of Ephraim, ‘Come, let us go up to Zion, to the LORD our God’” (Jeremiah 31:6). “But I will bring Israel back to their own pasture, and they will graze on Carmel and Bashan; their appetite will be satisfied on the hills of Ephraim and Gilead” (Jeremiah 50:19).
Although not specifically referred to in the New Testament, most of the hill country of Ephraim would have been in Samaritan territory.