Joshua 16:3, 10

Then it goes down westward to the territory of the Japhletites, as far as the territory of Lower Beth-horon, then to Gezer, and it ends at the sea.

However, they did not drive out the Canaanites who lived in Gezer, so the Canaanites have lived in the midst of Ephraim to this day but have been made to do forced labor.