Jacob's family moved to Egypt as seventy people, and came back as a federation of 12 tribes, over 600,000 men plus their families. (Actually, there were 13 tribal groups, as Joseph's two sons became the separate "half-tribes" of Ephraim and Manasseh, who settled on opposite sides of the Jordan River; but as the tribe of Levi did not have its own territory, they were 12 distinct geographical areas.)
As they conquered the land promised to their ancestor Abraham, they became three groups: two west of the Jordan, and one to the east. The tribes of Reuben; part of Manasseh; and Gad settled in the area known as Gilead, now part of the Kingdom of Jordan, east and south of the Sea of Galilee. They became less politically part of the West Bank tribal federations, and were overrun and taken into exile by the Assyrians as they expanded into the area in the 700's BC. This area became the Greek-speaking area of the Decapolis by New Testament times, but it is interesting that one of those Greek city-states was was named Gadara, the location of a herd of pigs going over the cliff. (Mark 5).
The West Bank tribes became two kingdoms. Judah was the family of the royal line of David. His name survives as "Jew", strictly speaking, referring to the people of the southern kingdom. Their territory was also the home of Simeon in the south and Benjamin along their northern border. It is interesting that in two places, the apostle Paul refers to himself not as a Jew, but a "Hebrew, of the tribe of Benjamin"; and that his Hebrew name is Saul, the same as the most famous Benjaminite, King Saul, the first king of the 12 tribes. The Kingdom of Judah (later Judea) remained more or less in a relationship with God, and while not all the kings were godly rulers, the tradition and the tribes survived the Assyrian attempt at conquest, the Babylonians, the Syrians, the Romans, centuries of dispersion, and now has regained a national home.
We find mention of Issachar and Zebulon fighting with Deborah against the Canaanites under Sisera. Later, the northern tribes rejected Solomon's son Rehoboam, and Jeroboam from Ephraim became the king of the tribes of the north; in fact, "Ephraim" was often used as a general term for the northern tribes. Jeroboam set up pagan idols in the north to give the northern tribespeople an alternative to Jerusalem (the capitol of the south) as a worship center. In a long and chaotic list of the Kings of Israel, as the northern federation became known, there was not one God-fearing ruler. They were conquered by the Assyrians and many of them deported to other parts of the Assyrian Empire, and lost their Israelite identities. Many of them fled to the south, but still retained their tribal roots--in Luke 2, the prophetess Anna that blessed Jesus as a baby is described as being from Asher.
Levi was the tribe of Moses and Aaron, and when Moses came down from Mount Sinai the first time to find the people having a wild and riotous party involving a golden calf, he called on his tribespeople to stop it and bring order. They were then "set apart to the Lord" and became the priests and servants of the Temple. They were given cities scattered throughout the country, but no separate territory of their own.
It is amazing that these tribal identities have survived over the centuries; there are still some Jews today who have ancient geneological records. One American author from a Russian Jewish family has said that although he personally was no longer observant he was often asked to participate in Jewish events because he had the geneologies to prove his heritage. Are we passing down a knowledge of God as our heritage?
LEAH: Reuben, Simeon, Levi, Judah, Issachar, Zebulon
ZILPAH (Leah's maidservant): Gad, Asher
RACHEL: Joseph: Manasseh, Ephraim; Benjamin
BILHAH (Rachel's maidservant): Dan, Naphthali