Deuteronomy 34:1

And Mosheh went up from the plains of Moab to the mountain of Nebo, to the summit of the height which is over against Jericho; and the Word of the Lord showed him all the strong ones of the land, and the mighty acts which would be done by Jeptha of Gilead, and the victories of Shimeon bar Manoah of tribe of Dan;

It is my belief that Joshua wrote from this verse onward, because once Moshe ascended, he wrote nothing further. Joshua must have written prophetically, as evidenced by God showed…, as well as God said to him…, and “He buried…” [: 6].

AND THE ETERNAL SHOWED HIM [MOSES] ALL THE LAND — all the Land of Israel beyond the Jordan [westward] — and then the verse states that He showed him even Gilead, as far as Dan. Now Moses was in the territory of Reuben, and half the hill-country of Gilead, and the cities thereof belonged to the children of Reuben, and the other half belonged to Menasheh. Therefore the verse before us must mean that [G-d showed Moses the whole Land] “from Gilead — must mean “from” the Gilead onward. as far as Dan.” Or it may be that there was [a place called] Gilead in the Lebanon in the Land of Israel, as it is written, thou art Gilead unto Me, the head of Lebanon. The verse mentions as far as Dan which is at the extremity of the border of the Land of Israel, as it is written, Go now to and fro through all the tribes of Israel, from Dan even to Beer-sheba. It mentions the land of Ephraim and Menasheh which were in the northern part of the Land of Israel, and the land of Judah was to the south, as it is written, Judah shall abide in his border on the south, and the house of Joseph shall abide in their border on the north, for Judah took all the south of the Land of Israel from the Jordan to the sea, and Dan took the north-west. It mentions Naphtali who was on the east, near Judah,, 19:34 [in speaking of the border of Naphtali]: and it reached… to Judah at the Jordan toward the sunrise. but it does not mention Asher and Issachar, for they were among Ephraim and Menasheh, as it is written [about the borders of Ephraim and Menasheh], and they reached to Asher on the north, and to Issachar on the east. It did not mention Simeon, for their inheritance was in the midst of the inheritance of the children of Judah,, 19:1. nor that of Benjamin whose border of their lot went out between the children of Judah and the children of Joseph,, 18:11. already mentioned near them. It states as far as the western sea which alludes to Zebulun who dwelt at the shore of the sea, or it may be that [Zebulun] is included [in the statement that G-d showed him] the south, and the plain [since the territory of Zebulun was in the plain at the sea]. It mentions the valley of Jericho because it is a deep valley, not visible from the top of the mountain [where Moses stood], but G-d showed it to him miraculously. In general then He showed him the entire inheritance of Israel, as it is written, This is the Land which I swore etc. Our Rabbis in the Sifre 357. have elucidated about these places mentioned in Scripture.
Now, the reason for this sight which He showed him was because the Land of Israel is full of all good things, and is the beauty of all lands. And since the great love with which Moses our teacher loved Israel was manifest to Him, He made him rejoice by beholding the abundant goodness with his eyes.

את הגלעד עד דן, “the region of Gilad as far north as Dan.” Moses describes the boundaries of the Land of Israel, which in the Book of Samuel I, is described as “from Dan to Be-er Sheva.