כָּל־הַפְּקֻדִים֙ לְמַ֣חֲנֵה דָ֔ן מְאַ֣ת אֶ֗לֶף וְשִׁבְעָ֧ה וַחֲמִשִּׁ֛ים אֶ֖לֶף וְשֵׁ֣שׁ מֵא֑וֹת לָאַחֲרֹנָ֥ה יִסְע֖וּ לְדִגְלֵיהֶֽם׃ (פ)
Semua orang yang tercatat dari perkemahan Dan berjumlah seratus lima puluh tujuh ribu enam ratus orang; merekalah yang harus berangkat paling akhir, menurut panji-panji mereka.
Siftei Chakhamim
They traveled in the shape of a box. Like Rashi explains in Parshas Bamidbar (2:9) — the banner of Yehudah was on the east, Reuven’s on the south, Ephraim’s on the west and Don’s on the north. Therefore they had to spread out to a width of two banners and consequently [Don] had to be heavily populated. However, according to the opinion that they traveled one after the other in the shape of a beam, and deriving this from “gatherer for all the camps” — even if Don was not heavily populated, they could gather whatever was lost. You might ask: The tribes [traveling under the banner] of Yehudah were more populous than the tribes [traveling under the banner] of Don, because the tribes [traveling under the banner] of Yehudah comprised 186,400 while the tribes [traveling under the banner] of Don totaled only 157,600, as the Torah writes in Parshas Bamidbar (2:9, 31). (Gur Aryeh) answers: Yehudah traveled first, given that he was the king, and therefore the last to travel was Don who had the largest population after Yehudah.