Numbers 2:17-18

17The Levites must march next. The Levites must carry the Tent of Meeting. They must march between the first two groups of tribes and the last two groups of tribes. Each man must be in his own place. They must march with their flag.

18The tribe of Ephraim must be on the west side of the Tent. They must have their flag with them and they must live in groups. The leader of the tribe of Ephraim is Elishama, the son of Ammihud.