Judah and Samaria

When the Israelites came out of Egypt the first portions they conquered of the Promised Land were the regions east of Jordan. These went to the Tribes of Reuben, Gad, and half Manasseh (Numbers 34:14, Deuteronomy 3:12, 16).
 Even though these Tribes had already received their lands they were obliged to continue the conquest of all the Land together with the other Tribes (Joshua 1:12-14). The Israelites then crossed the Jordan and conquered the south and center which included the future areas of Judah and Samaria. These areas belonged to the Tribes of Judah, Ephraim and Manasseh. The "remaining seven tribes" (Joshua 18:1-4) were were then conquered and distributed. After that a scattering of 48 cities, some from each Tribe, were given to the Tribe of Levi (Joshua 21:1-41, cf. Numbers 35:7). There were 12 tribes of Israel. They inhabited all the Land of Israel which encompassed a good portion of the Middle East. This included Judah and Samaria.

After the death of King Solomon the Israelite Tribes divided into two sections (1-Kings 12:16-19). The Kingdom of Judah was in the south centered on Jerusalem. The Kingdom of Israel, also referred to as Samaria, was in the north with its capital in the city also known as Samaria. The Assyrians attacked the northern Kingdom and exiled its inhabitants in stages. The Exiles included Israelites from east of the Jordan (1-Chronicles 5:26); the Tribes in the north (2-Kings 15:29); and Samaria (2-Kings 17:6). According to Assyrian inscriptions, Biblical indications, and Midrashim many were also taken, by Assyria under Sennacherib, from Judah. Meanwhile the original Hebrew inhabitants of Samaria had been exiled. Before the exile many had moved to Judah and there were also more Israelite refugees from Samaria who followed them. The fact that a minority of Israelites moved to Judah is confirmed by the Bible, Midrashim, and archaeological findings. The population of Judah therefore included many from the Northern Ten Tribes though the bulk of them had been taken away by the Assyrians. In the south Judah was the dominant Tribe so all inhabitants of the region were named after Judah. That is where the name "Jew" comes from. The Ten Tribes exist but they were exiled and last awareness of their ancestry. In the future this will change. For the present the only section of the Israelite nation that is recognizable as such is the Jewish People. The Jewish People encompass the Tribes of Judah, Benjamin and Levi IN ADDITION TO minority representatives of all the other Tribes. God gave ALL the Land to the Israelite Tribes. The Jews are responsible for their own lands and the lands of the rest of Israel now in their possession.

In addition there was also a people known as Samaritans. They were originally Gentile pagans who had been brought into the land by the Assyrians. Samaria is where the Samaritans lived when the Assyrians settled them. The Samaritans however were not Israelites. They were descendants of heathens who were only partially Judaised which is why the Jews kept a distance from them. The Samaritans had been brought in by Assyria from other nations to take the place of the former Israelite inhabitants who had been exiled (2-Kings 17:6, 24-29).

Samaria had formerly belonged to the Tribes of Ephraim and Manasseh and Issachar. Judah was to the south and included the area of Benjamin north of Jerusalem and encompassing the Benjamin settlement of Beth-el. The Ten Tribes had been mostly exiled but representative portions were still to be found with Judah. The presence of elements from those tribes who had been in Samaria is mentioned in the Bible. King Josiah son of Amon ruled over Judah and the rest of the Israelite area about 100 years after the Ten Tribes had been exiled. Josiah purified of idolatry the ruins of cities in Manasseh, Ephraim, Simeon, "even unto Naphtali" (1-Chronicles (NASB) 34:14). This affirms that the cities of Samaria were then in ruins and presumably uninhabited. [A stella recalling King Josiah of Judah has been found in Beth-Shean in North Israel in the former area of Manasseh.] There was a small remnant from Manasseh and Ephraim and also of other tribes together with Judah. Contributors to the Temple Fund in the time of King Josiah were mentioned as from "Manasseh and Ephraim, and from all the remnant of Israel" (2-Chronicles 34:9). There were therefore some members from these tribes with Judah at that time. There were minorities present of the other Tribes as well BUT since their main Tribal bodies had been exiled they are generally subsumed together with Judah.

The Midrash Seder Olam (ca. 150 CE) points out that in the Books of Ezra and Nehemiah are found lists of the families who returned to the Land of Israel from Babylon. ONLY families from the Tribes of Judah, Benjamin, and Levi are mentioned. This is despite the fact that minority remnants of the other tribes were there. There is a disparity of 20% between the total census numbers and the total listed families from Judah, Benjamin, and Levi. The Midrash Seder Olam opines that numerically the Jews of Judah who returned from Babylon were these 80% from the former Kingdom of Judah (i.e. Judah, Benjamin, and Levi) while the 20% who were not listed are minority remnants from the Northern Tribes.
Nachmanides explains that the Lost Ten Tribes were destined to reach their Tribal Expression in Exile. Therefore, as far as Scripture is concerned they had been ALL exiled and disappeared.

Nachmanides (1194-1270):
 "Those from the Tribes of Ephraim and Shimeon from Israel that were present with Judah were they who dwelt in the Land of Judah or perhaps to some degree also those who had dwelt in their own territories adjoining Judah and had fled to Judah. They are referred to in a general sense as from Israel [in 2-Chronicles 35:18] and not by their specific tribes since they represented only a small portion of their tribe. These are they who returned under Ezra with the Jews from Babylon. They were not expressly mentioned by their tribes since they were attached to Judah. They all settled in the cities of Judah. There was no Redemption for the Ten Tribes who remained in exile."
 Book of Redemption (Sefer HaGeulah).

It should be emphasized that most of the Ten Tribes did not return. They will do so in the End Times, as prophesied.

Ezekiel 37:
 21 Then say to them, Thus says the LORD God: Surely I will take the children of Israel from among the nations, wherever they have gone, and will gather them from every side and bring them into their own land; 22 and I will make them one nation in the land, on the mountains of Israel; and one king shall be king over them all; they shall no longer be two nations, nor shall they ever be divided into two kingdoms again.

See Also:
 The Completeness of the Exile
 http://www.britam.org/CompleteEx...

The Stages of Exile
 http://www.britam.org/isaiah/Isa...

The Present-Day Jews at Present Represent ALL ISRAEL since for the time being they are the only ones still recognizable as such.
 This had been predicted by the forefather Jacob.

Genesis 49:
 10 The scepter shall not depart from Judah,
Nor the ruler's staff from between his feet,
Until Shiloh comes,
 And to him shall be the obedience of the peoples.

Rabbi Manasseh ben Yisrael (1604-1657) explained (in line with theHebrew text and other Rabbinical authorities) this verse from the Hebrew to mean:

Genesis 49:
 10 The scepter [Hebrew: "shevet" i.e. Tribe or Staff of Being a Tribe] shall not depart from Judah,
 Nor the ruler's staff from between his feet,
 Until Shiloh comes,
 And to him shall be the obedience [Hebrew : "kehast" i.e. ingathering] of the peoples [i.e. other tribes of Israel.]

This he explains meant that the Sign of being a Tribe would not depart from Judah but it would be missing from the other Tribes. This would continue until the Messiah ["Shiloh"] appears and he will make known to all the rest of Israel what Tribe each one belongs to.

Just as King Josiah of Judah reigned over all of the lands of the other Tribes so too must the Jews of today endeavor to do so.
 There is a Positive Commandment to conquer ALL the Land of Israel.
See:

The Commandment to Settle the Land of Israel, Part 1
 by Rabbi Eliezer Melamed
 http://www.yeshiva.co/midrash/sh...

Members of ALL the Israelite Tribes have an obligation to help conquer and settle with Israelites ALL the Land of Israel. This is regardless as to whether the areas in question pertain to their own Tribe or not. This does not mean that under all and any circumstances Israel needs to attack its Gentile neighbors.
 It does however imply that once the Lands have come into the hands of Israel and Israel needs them and can make use of them they should not be surrendered.

In our time Judah is the fore-runner going before the other Tribes to prepare the way (Hosea 6:11, Jeremiah 33:7-11). Judah needs to be strengthened and encouraged. The Captivity of the Jews (Judah) and of the Lost Ten Tribes (Israel) will return and be rebuilt in the Land of Greater Israel from the Nile to the Euphrates. We will be forgiven for our sins and purified of the impurity caused by our bad habits, harmful surroundings, and past lifestyles, and the crippling spiritual hang-ups these have caused us.

Micah 4:8 predicts that in the end times at the beginning of the return "THE FIRST DOMINION" in the final return of Israel shall be "TO THE DAUGHTER OF JERUSALEM" meaning descendants of Judah. In addition to Micah 4:8, Hosea 6:11 says that Judah will lead the way for the other Tribes and prepare the path for their return. Rabbi Zvi Hirsch Kalischer (1795-1874) noted that this verse refers to the End Times when Judah (i.e. the Jews) will prepare the way for the Return of the Ten Tribes.
 Judah and Samaria are part of the Promised Land. They are even more than that in so far as much of the Biblical Narrative takes place in those regions.
 They are CORE AREAS and at least as important as all other Israelite regions.