Verse 16: So Joshua took all that land, (Josh 12:8) the hills, and all the south country, (Josh. 10:41) and all the land of Goshen, and the valley, and the plain, and the mountain of Israel, and the valley of the same…
[He took, וַיִּקַּח] He possessed (the Chaldean in Masius). For concerning the Kings taken and the cities conquered לָכַד, to capture or take, is used. But לָקַח is also thus taken (Masius).
[All the land] Hebrew: all that land. There the reading is to stop, on account of the Rebia (֗) accent. Here he places many dominions under the eyes of the readers, as it were, so that they, comprehending such an abundance of so easily accomplished works in a single glance, as it were, might more clearly understand that God lavishly discharged the obligation of His promises (Masius).
All that land, of Canaan, whose parts here follow.
[Mountainous land] Of which it was spoken on Joshua 10:40. But here the plain is able to be set in opposition to it. The like is said at the same time concerning the south country. Now, the western tract is that whole region from Kadesh-barnea unto Gaza, concerning which Joshua 10:41. For that, at least with respect to the Tribe of Judah, was sloping down toward the West (Bonfrerius).
The hill, or, the mountain, that is, the mountainous country, to wit, of Judea, as may seem, 1. Because in the following enumeration he begins in the south parts, where there was an eminent mountain, Numbers 13:17. 2. Because a considerable part of Judea was called the hilly or the mountainous country, Luke 1:39, 65, which is not likely to be omitted in this particular description of the land; the rather because Hebron, one of the places taken by Joshua, Joshua 10:36, 37 was in the mountain of Judah, Joshua 20:7. 3. Because this is here distinguished from the mountain of Israel, and therefore most likely to be the mountain of Judah, especially if you compare this with Joshua 11:21, where having mentioned the mountain in general, from which Joshua cut off the Anakims, he comes to particularize, and names only two, all the mountain of Judah, and all the mountain of Israel. All the south country, that is, not only the mountainous part, but all the country of Judea, which lay in the southern part of Canaan, and oft comes under the name of the south, as Numbers 13:22, 29; 21:1; Joshua 10:40; 18:5, etc. The land of Goshen; of which see Joshua 10:41. The vale; the low countries. The plain; the fields or champaign grounds.
[And the mountain of Israel] Question: What is the mountain of Israel here? Response: Some particular mountain is indicated, but it is obscure which that might be. This phrase does not occur except in Ezekiel 17:23; 20:40, and that metaphorically (Bonfrerius). 1. When the mountain of Judah is distinguished from the mountain of Israel, the mountainous places around Samaria are undoubtedly called the mountain of Israel, which were thus called after the secession of the ten tribes (Masius). Objection: But, since Joshua wrote this book, who would believe that this name was given prophetically by Joshua so long before the secession (Bonfrerius)? Response: Masius hence concludes that this book was not written by Joshua, but by another long after him (Lapide). Whoever composed this history from the Sacred annals made use of the names of his own age (Masius). 2. The Mountain of Israel, or of Jacob, appears to be the mountain of Bethel, on which Jacob had that famous vision, Genesis 28, and received Divine promises concerning the land of Canaan, etc., unto which he also returned, Genesis 35, and there remained for some time, and built an altar to God (Bonfrerius). 3. Or, if this does not quite satisfy, let it be some mountain near to Shechem, or Gerizim, or some other within that field that Jacob had bought, Genesis 33:19 (Bonfrerius out of Salmasius, Cajetan in Lapide). The Mountain of Israel is where Jacob had formerly dwelt (Munster).
The mountain of Israel; either, 1. Some one particular and eminent mountain, possibly the hill of Samaria, mentioned 1 Kings 16:24; or rather, 2. The mountains or mountainous country of Israel. See above on this verse.
The vale of the same, that is, of Israel.
 Hebrew: וַיִּקַּ֙ח יְהוֹשֻׁ֜עַ אֶת־כָּל־הָאָ֣רֶץ הַזֹּ֗את הָהָ֤ר וְאֶת־כָּל־הַנֶּ֙גֶב֙ וְאֵת֙ כָּל־אֶ֣רֶץ הַגֹּ֔שֶׁן וְאֶת־הַשְּׁפֵלָ֖ה וְאֶת־הָעֲרָבָ֑ה וְאֶת־הַ֥ר יִשְׂרָאֵ֖ל וּשְׁפֵלָתֹֽה׃
 For example, Joshua 10:42: “And all these kings and their land did Joshua take (לָכַד) at one time, because the Lord God of Israel fought for Israel.”
 Hebrew: אֶת־כָּל־הָאָ֣רֶץ הַזֹּ֗את.
 The Rebia is among the strong disjunctive accents.
 Claudius Salmasius, or Claude Saumaise (1588-1653) was a French Protestant scholar of classical antiquity. He succeeded Joseph Scaliger in the professorship at Leiden.
 Hebrew: וּשְׁפֵלָתֹה.
 שְׁפֵלָתֹה is indeed an irregular form. The expected pointing for the third person, singular, masculine suffix would be שְׁפֵלָתוֹ; for the third person, singular, feminine suffix, שְׁפֵלָתָהּ.