Every man of the children of Israel shall pitch by his own banner, with the banner of their father’s house. They shall pitch far off, around the tabernacle of the congregation (Numbers 2:2, HBFV throughout).
The tents of Moses and Aaron, also located in the center of the encampment with the tabernacle, were placed in front of the its eastern entrance.
And those who camp before the tabernacle toward the east, before the tabernacle of the congregation eastward, shall be Moses, and Aaron and his sons, keeping the charge of the sanctuary for the charge of the children of Israel. And the stranger that comes near shall be put to death (Numbers 3:38).
The Eastern Grouping
The first grouping of tribes in the wilderness encampment would face East toward the rising sun (which was the general direction they were traveling in - Numbers 2:3). They would be the first to leave the camp. Next in line to leave would be the tribes on the South side, then the Levites who serviced the tabernacle, then those on the West and finally those facing north.
The wilderness tents from the tribes of Judah, Issachar and Zebulon were placed together on the eastern side of the tabernacle and were collectively under Judah's banner. Judah, Issachar, and Zebulun were the three youngest sons of Jacob's (Israel's) wife Leah.
And those who pitch on the east side toward the rising of the sun shall be those of the banner of the camp of Judah, throughout their armies . . . (Numbers 2:3).
Judah was chosen to lead this first set of Israelites out of their wilderness camp not only because it was the most numerous tribe of Jacob, but also because it was prophesied that the scepter of rule would never leave them (Genesis 49:10). Christ, in the New Testament, is called "the Lion of the tribe of Judah" (Revelation 5:5). The number of fighting men on this side of the camp totals 186,400.
The Southern Grouping
The tribal camps of Reuben, Simeon and Gad were placed together on the southern side of the tabernacle and were collectively under Reuben's banner. Reuben, born through Leah, was the oldest son of all Jacob's children, with Simeon being the second oldest. Gad was born from Jacob and Leah's handmaid Zilpah. All together, they totaled 151,450 fighting men.
On the south side shall be the standard of the camp of Reuben, according to their armies . . . (Numbers 2:10).
The Western Grouping
The Western side of the wilderness encampment contained the tribes of Ephraim, Manasseh and Benjamin. Benjamin was born of Jacob's favorite wife Rachel. Ephraim and Manasseh were the product of Rachel' son Joseph. They were 'adopted' by Jacob as full tribes (see Genesis 48). This group of Israelites contained 108,100 fighting men.
On the west side shall be the banner of the camp of Ephraim, according to their armies . . . (Numbers 2:18).
The Northern Grouping
The tribal camps of Dan, Asher and Naphtali, collectively under Dan's banner, were placed together on the northern side of the tabernacle. Dan is the oldest son of Jacob and Bilhah (one of Rachel's slaves). They totaled 157,600 men who could fight and were the last group in the wilderness to leave.
The banner of the camp of Dan shall be on the north side of their armies . . . (Numbers 2:25).
According to the Bible, the total strength of Israel's wilderness camp army was 603,550 men.
What About the Levites?
The tribe of Levi pitched their tents close to the wilderness tabernacle which they served. They left the camp after the southern grouping of the tribes but before the western grouping. They ended up marching in the middle of all the tribes with two divisions in front and two in back as they carried the Tent of Meeting or tabernacle (Numbers 2:17).
And the tabernacle of the congregation shall go forward with the camp of the Levites in the midst of the camp. As they camp, so they shall go forward, each man in his place, by their banners (Numbers 2:17).
Because God dedicated the Levites to serve as priests he did not have them numbered among Israel's wilderness camp army (Numbers 2:33). That said, some 38 years later a second census was carried out by Moses where the Levites were counted. The tribe consisted of three major clans (Numbers 26:57) and five subclans. This census found there existed 23,000 males, one month old or older, within the tribe of Levi (Numbers 26:62).