Half the Tribe of Menasheh

We do not find that the tribe of Menasheh requested a portion of land in Ever haYardein (the East Bank). If so, why is half the tribe given a portion there (Bemidbar 32,33)?

1. The Ibn Ezra says that they did request their inheritance there, but it was not mentioned, as only one-half their tribe requested it. [This opinion seems to be contradicted by the Yerushalmi Bikurim that states that according to Rabbi Yossi of Galilee one does not bring the first ripened fruit as Bikurim from the Trans-Jordan because the verse says that one must bring it from "the land that You have given me," (Devarim 26:10). The Trans-Jordan was not given by HaShem's directive, but rather as a result of the request of the tribes. The Gemara says that according to this Bikurim should be brought from the area of the half of Menasheh tribe. This implies that they did not request that land.]
2. The Ramban writes that when Moshe realized that there was so much land available he offered any other tribe that was willing to live there a portion. Half the tribe of Menasheh accepted this offer.
3. The Chizkuni on Bereshis 44:13, "Vayikru simlosom," writes that Menasheh was sent to retrieve the stolen goblet, a false, trumped-up charge against Benyamin, which caused the tribes to rent their garments. Therefore, Menasheh’s descendants were punished by having their inheritance ripped into two parcels, one in Eretz Yisroel and one outside Eretz Yisroel.
4. The Tzror Hamor writes that Moshe gave them a portion with the tribes of Gad and Reuven so that the merit of Yosef should protect the tribes of Gad and Reuven.
5. The Netziv on Devarim 3:16 writes that they were given a portion in the Trans-Jordan because the level of Torah there would be very weak and half the tribe of Menasheh, in particular the family of Mochir, would inject a powerful dose of Torah into the Trans-Jordan community.
6. The Sha"ch writes that this was done to avoid bnei Yisrael later claiming that those living on the other side of the Jordan River are not part of bnei Yisrael. The tribe of Menasheh was picked because Yosef embodies all bnei Yisroel, as indicated by verse in Tehillim and Amos. As well, the daughters of Tzelafchod resided in Eretz Yisroel, while their fathers-in-law resided in the Trans-Jordan. This created an awareness between them that they remained brethren.
7. The Lubavitcher Rebbe writes that half the tribe of Menasheh settled in Ever haYardein, expressing their connection to Moshe, his Torah, and to the full (future) Land of Israel. Menasheh’s love of the Land for no ulterior motive reflects the future inheritance of the Land.

WHY DID THE TRIBES OF REUVEN, GAD AND HALF OF MENASHEH RECEIVE PORTIONS OF LAND OUTSIDE OF ERETZ YISROEL?

Rabbi Menachem Azarioh of Panu in Asarah Maamoros provides quite an innovative approach to this question. He explains that the three sons were born from an “improper” type of union that negatively affected the child (and affected their descendants’ tribe).

Reuven was conceived with Yaacov's believing that he was with Rochel, while in truth he was with Leah (Bereshis 29,25). This type of union is improper (Nedarim 20b).

Gad, likewise, was born of such a union. When Leah gave her maidservant Zilpah to Yaacov for him to sire a child, Yaakov was not aware that it was Zilpah. He thought it was his wife Leah.

Menasheh was the son of Osnas (the wife of Yosef). She was the daughter of Sh'chem and Dinah. As such, he had half his soul tainted, coming from Sh'chem. Therefore, ½ his tribe was not able to receive a portion in Eretz Yisroel. Menasheh, the first-born, absorbed all the impurities imparted to Osnas from Sh'chem (therefore, Yaacov switched his hands favoring Efrayim to receive the dominant blessing).