Mount Ephraim (Hebrew: הר אפרים), or alternately Mount of Ephraim, was the historical name for the central mountainous district of Israel once occupied by the Tribe of Ephraim (Joshua 17:15; 19:50; 20:7), extending from Bethel to the plain of Jezreel. In Joshua's time (Joshua 17:18), approximately sometime between the 18th century BCE and the 13th century BCE, these hills were densely wooded. They were intersected by well-watered, fertile valleys, referred to in Jeremiah 50:19.
Joshua was buried at Timnath-heres among the mountains of Ephraim, on the north side of the hill of Gaash (Judges 2:9). This region is also called the "mountains of Israel" (Joshua 11:21) and the "mountains of Samaria" (Jeremiah 31:5, 6: Amos 3:9).
'Then Jeroboam built Shechem in mount Ephraim, and dwelt therein; and went out from thence, and built Penuel. And Jeroboam said in his heart, Now shall the kingdom return to the house of David:(Ephraim was the new king after the pass of the King of Solomon.) 
This article incorporates text from a publication now in the public domain: Easton, Matthew George (1897). Easton's Bible Dictionary (New and revised ed.). T. Nelson and Sons. Missing or empty