The tabernacle is specifically ordered by God insofar as to its directional orientation. The gate, the door and the veil (all portals of entry) must face the east, “toward the rising of the sun”. Likewise, the tribes are commanded where they must camp relational to the tabernacle.
East, just beyond the priesthood was assigned to the camp of Judah. This is the most favored position. It seems that Judah was the chief of all camps on the east. On either side of Judah was Issachar and Zebulon, all of these were the sons of Leah. The favor of the camps begins at the east and goes clockwise around the tabernacle.
On the South, was assigned to the camp of Reuben (who was actually the firstborn of Jacob and Leah, but seems to have lost his favored position due to his sin with Bilha). Joining Reuben here are Simeon (Leah’s) and Gad (from Leah’s handmaid Zilpah).
On the West, the tribes are 100% represented by the seed of Rachel. Jacob would have given her the most favored position, but God chose Leah. Ephraim is the chief of these camps, bordered by Manasseh and Benjamin. Note that Rachel and Leah are here opposite to each other (as east is opposite to the west).
The North is the camp assigned to Dan, the least favored position. He is joined here by his brother Naphtali (both born of the handmaid Bilha) and Asher (the other son of handmaid Zilpah).