Shared ground
Joshua 12:7–8 works like a heading. It introduces a new list: the kings Joshua and “the children of Israel” defeated west of the Jordan (explicit). The text frames the conquest with broad boundary markers (from Baal-gad in the Lebanon valley down to Mount Halak rising toward Seir) and then says Joshua “gave” that land to Israel’s tribes as their possession, in line with their allotted divisions (explicit).
The passage also presents the land as varied and wide-ranging by naming major terrain zones (hill-country, lowland, Arabah, slopes, wilderness, the South/Negev) and by using a short list of people-groups as a summary label for who was associated with that territory (explicit).
Where interpretation differs
Some readers take the geographic markers as close to a precise, mappable border; others see them as a broad north-to-south span meant to orient the reader rather than define exact lines (inference).
Some understand the terrain terms as distinct regions; others think the terms overlap and function as a “full-coverage” description (inference).
Some take the people-group names as straightforward references to the residents Israel displaced; others think the names can also serve as broader labels for political/cultural identities in the land and not always a simple census-like statement (inference).
Why the disagreement exists
The passage is intentionally compressed because it introduces a longer catalog that follows. It uses shorthand place names and category terms (for landscapes and peoples) that can be hard to match one-to-one with modern maps or with a single social meaning.
What this passage clearly contributes
It ties the coming king list (12:9–24) to two outcomes: (1) identifiable victories “westward” under Joshua’s leadership, and (2) land transfer to Israel’s tribes “according to their divisions.” It also signals that the conquest being summarized is meant to be read as spanning multiple environments and multiple local identities within Canaan.